Plummeting Batting Averages Are Due to Far More Than Infield Shifting, Part One: Fielding and Batting Strategy

In 2022, the Lords of Baseball decreed that the full infield shift, which had become commonplace in baseball, would be banned. Since the 2023 season, all four infielders must be within the outer boundary of the dirt, with two on each side of second base and no switching sides. After a violation, the wronged team can either accept the outcome of the play or continue the previous at-bat with a ball added to the count.

In a press release, Major League Baseball claimed that “these restrictions will return the game to a more traditional aesthetic by governing defensive shifts, with the goals of encouraging more balls in play, giving players more opportunities to showcase their athleticism, and offsetting the growing trend of alignments that feature four outfielders.”1 Partial shifts, with one of the middle infielders just to their side of second base, are still allowed.

In contrast with two other rule changes announced at that time—the pitch timer and larger bases—MLB provided no factual rationale for these restrictions. However, some commentators provided one: a significant drop in batting averages over time. For example, Matt Snyder noted that the composite .243 batting average for 2022 was the lowest since 1968, the Year of the Pitcher, when the two major leagues batted .237.2 In fact, the league also batted .245 in 2020 and .244 in 2021, for a combined .243 average from 2020 to 2022. That’s the fourth-lowest three-year average since 1901, trailing the spans that ended in 1968, 1909, and 1969 by less than one-thousandth of a percentage point. Snyder and others implied that the motivation for the ban was a desire for more base hits, additional baserunners, and a more attractive product that would draw more fan interest.

Figure 1 shows the ebbs and flows of batting average in the American and National Leagues since the start of the live ball era in 1920.4 Note the sharp drop starting in 2007. From 2007 to 2022, the league batting average fell 25 points from .268 to .243. This essay will focus on this period of time.

If the goal is returning the batting average to the level of 2007, banning the shift will not be enough to accomplish it alone. This drop was the result of several factors, of which the infield shift was just one. Shifting among outfielders has probably been more consequential. Intentional revisions in batting strategy, favoring fly balls over grounders, have also had a discernible impact. These three factors were likely responsible for most of a 13-point decrease in batting average on balls in play (BABIP) over this time period. But looming over all of this is the much-discussed rise in strikeouts, which probably accounts for the bulk of the remaining 12 points. The rule change will have no effect on the last three factors, and there is no reason to believe that their impact will change dramatically in the coming years without either further rule changes or revisions in strategy.

The goal of this essay is an in-depth examination of the effect of the first three of these factors. The infield shift has garnered the most attention and is the object of the rule change, so it will receive the bulk of the discussion here. A second essay on factors impacting strikeout rate will appear in the future.

 

 

CHANGES IN BASIC BATTING METRICS FROM 2007 TO 2022

I begin this examination with two graphs, Figures 2 and 3. The first shows counting stats in each year up to 2022, the last season of the full infield shift.5 In order to keep the scale consistent, I have used the ratio between each season’s totals and the totals in 2007 rather than the raw numbers.6

Walks have generally bounced between 3.0 and 3.5 per game starting in the 1950s, so any trends implied here may be an illusion. Homers, at 1.02 per game per team in 2007, increased starting in 2016 and reached a peak at 1.39 in 2019, but appear to be returning to their previous level ever since. In contrast, hits have dropped steadily, from 9.25 per team per game in 2007 to 8.04 in 2020. Singles, doubles, and triples have generally followed the same path. Strikeouts have changed the most conspicuously, rising from 6.62 per team per game in 2007 to 8.81 in 2019, though they fell to 8.40 in 2022.

Turning to averages, batting average fell from .268 in 2007 to .243 in 2022 as discussed earlier. On-base average fell a similar amount, 24 points from .336 to .312. Slugging average was a roller-coaster ride, down from .423 in 2007 to .386 in 2014 as doubles and triples fell, then up to .435 in 2019 as homers increased, but back to .395 in 2022 as homers and triples dropped (and doubles were up only a bit). The shift ban is specifically targeted at BABIP. To add some historical context, BABIP stayed in the .280s from 1973 to 1992. It jumped to .294 in 1993 and stayed in the mid .290s through low .300s until 2020. The 2007 figure of .303 was the high-water mark. The drop in this decade brought BABIP down to levels not seen since the early 1990s.

The following three sections cover the three factors behind the drop in BABIP: infield shifting, outfield shifting, and changes in batting strategy.

 

 

INFIELD SHIFTING

Philadelphia’s Cy Williams is generally considered the first batter to regularly fall victim to defensive shifts back in 1923.7 But there is evidence of infield shifts being used as early as 1877.8 Another Williams, Ted, at least occasionally faced both infield and outfield shifts beginning in 1946. Thereafter, shifts were applied from time to time against lefty pull hitters, including Willie McCovey, Boog Powell, and David Ortiz. The value of the shift was intuitive. An early study from the Elias Sports Bureau revealed that, even with fielders generally shading in that direction, when there was no shift, batters had higher batting averages on balls hit to their pull side than to the opposite side (with hits up the middle ignored). Of 84 players with at least 400 balls in play in 1990 (excluding switch-hitters, unless they accumulated 400 from one side of the plate), 71, or 84.5%, hit for a higher average on their pull side.9

By the end of the aughts, the Rays had begun the final era of the infield shift. As spray angle data became more widespread, other teams quickly followed their lead. From 2011 to 2015, full shifts increased from 1,389 per year to 11,524, while partial shifts increased from 968 to 6,214.10 The distinction between full and partial is critical; Rosales and Spratt noted that between 2010 and 2015, batting averages on grounders and short line drives were actually higher with partial shifts (.265) than with no shift at all (.258). Sports Information Services’ Mark Simon came to a similar conclusion for the 2017 season, with weighted batting averages of .271 with no shift and .269 with a partial shift.11

According to Baseball Savant, by 2022 the full shift was used 60,779 times.12 There is no question that it was successful in reducing batting averages. Figure 4 includes batting averages and BABIPs for batters facing either a full shift or no shift between 2015 and 2022.

Over those eight seasons, the league batted .240 with a full shift and .252 with none. The difference between the two widened to 19 points by 2022 (.229 and .248). Without strikeouts to mask the effect, the divergence in BABIP was even greater: .279 with a full shift and .300 with no shift. In 2022, the difference was 26 points: .273 with a full shift and .298 with no shift. However, these metrics mask significant differences based on batter handedness across a wide range of metrics. Figure 5 breaks down the results during full shifts by batter handedness.

All told, right-handed batters consistently had higher batting averages and BABIP against the shift than left-handed batters. In fact, the righty advantage went beyond batting average. Table 1, offered by Russell Carleton, compares performance at the level of the individual batter with and without shifts for batters with more than 50 non-shifted PAs between 2015 and 2019; these tendencies remained in place through 2021 and the first half of 2022.13

First, when the defense was shifted, walk rates increased enough to make up for at least part of the decrease in singles. Going into more detail, pitch-tracking data revealed that when the defense was shifted, pitchers threw inside more often to take advantage of the infield being stacked to the pull side and to discourage hitting to the opposite field, resulting in more inside pitches that were called balls.14 Pitchers were also more likely to throw balls above the strike zone.

The major takeaway is that whereas left-handed batters were hurt by shifts, right-handed batters were helped by them. As Carleton observed, part of the reason for this discrepancy was the difference in fielder positioning. Against left-handed batters, the left side of the infield was patrolled by the infielder with the greatest range, the shortstop. Against right-handed batters, the right side of the infield was covered by the infielder with the worst range, the first baseman, who had to stay close enough to the base to take throws from the other infielders. Righties were able to take advantage of the large hole on the right side of the infield. Carleton concluded that they essentially faced only partial shifts, which were hardly better for the defense than no shift at all.15

 

 

Table 2, once again courtesy of Carleton, shows the difference in BABIP broken down by whether the ball was pulled.16

Because of the longer throw from the left side of the infield, right-handed batters fared better than left-handed batters when they pulled the ball, whether into a standard defensive alignment or a shift. But the real kicker is that because shifts against right-handed batters were partial, their loss of 36 points of batting average on pulled grounders was counterbalanced by their gain of 39 points on non-pulled grounders. On the other hand, not only did left-handed batters lose out when they pulled the ball due to the shorter throw to first, they also lost out when they went the other way, because they faced an optimally placed shortstop rather than a first baseman who was tethered to the bag.

Right-handed batters also fared better on line drives when the defense was shifted. On line drives hit at a spray angle of between 20 and 35 degrees (roughly the area between the first and second basemen in a standard alignment), right-handed batters were more successful to the tune of 27 points of BABIP.17 All told, from 2015 to 2022, left-handed batters had a .315 wOBA with no shift, better than the .312 wOBA of right-handed batters. But against a full shift, lefty wOBA was .319, far below the righty wOBA of .341. As a result, Sports Info Solutions recommended that teams not shift against right-handed batters who didn’t pull at least 80% of their batted balls to the infield. By 2021, teams seemed to notice. Carleton noted that while overall shifting against lefties increased slightly from 50.2% in 2020 to 51.5% in 2021, it dropped markedly against righties, from 23.0% to 16.8%.18

In conclusion, the shift had little impact on offense, as the resulting benefits for right-handed batters more than made up for any detriment to lefties. Repurposing the wOBA figures from the previous paragraph, wOBAs against the shift were higher for both right-handed and left-handed batters. However, these overall wOBAs are biased in that shifts were employed against better batters. Carleton’s calculations in Table 1 account for that bias and show that while the full shift did hurt lefty hitters a bit, it helped righties get more hits and increased walks for everyone. As will be covered later, it also sparked a strategic decision to beat shifts by hitting more homers.

In addition to the shift, Robert Arthur noted a general tendency for fielders to play more deeply that started by 2015 (if not earlier, as that was the first year Statcast’s defensive positioning data became publicly available). Despite their lack of positional flexibility given their need to be close to the base, first basemen had moved back a foot or so on average by 2017. Shortstops had shifted backward about two feet by 2019. Second basemen were back about four feet by the first month of 2021. The most significant drop was by third basemen, about nine feet by 2020. Of course, some of this was an artifact of general infielder shifting given that infielders were often placed in the outfield, and in fact there was little or no impact on BABIP for most of the infield. However, third basemen had actually moved back even more, about 10 feet, on plays in which there was no shift. As a consequence, the BABIP on balls hit to third dropped an incredible 40 points between 2017 and the beginning of 2021.19 In a follow-up, Arthur noted that balls hit up to 175 feet away from home plate were less likely to become hits over that period, with BABIP down over 100 points for those between 120 and 150 feet.20 Next, we turn to a type of shift that worked far better for the defense.

OUTFIELD SHIFTING

It is more difficult to measure the impact of shifting in the outfield. Infield shifting can be measured by the location of the fielders in relation to second base. In a presentation at the 2019 SABR Analytics Conference, Sports Info Solutions’ Brian Reiff pointed out that to define an outfield as shifted, one must consider how many outfielders have moved, what constitutes their starting point, and the distance from it that would count as a shift, all while keeping in mind issues such as batter handedness and ballpark dimensions.21

According to Sports Info Solutions (SIS), in 2017, left, center, and right fielders respectively stood an average of 296, 318, and 294 feet from home plate. Left fielders were stationed at an average spray angle of 26.9 degrees toward left field, right fielders were stationed an average of 27 degrees toward right, and center fielders were very nearly dead center. Those measurements constitute the average starting point for each outfielder, but there was significant variance. On the average play, the starting positions of the three outfielders were a combined 40 feet from those locations.

SIS defined an outfield as shifted if the total distance, adjusted for all of these factors, was greater than 110 feet. As with infield shifts, the number rose in the late 2010s. Mark Simon reported 2,814 such shifts in 2018, a 28% increase over 2017, and an astounding 89% increase from 2016.22 Overall, the greater the deviation from average, the more effective the outfield positioning. According to Reiff’s paper, OPS was at or above .750 for deviations of 30 feet or less, dipped below .700 at 70 feet, below .600 at 90 feet, and was just over .500 for 120 feet. The more extreme the batter’s spray angle tendencies, the more likely they were to face a shift.

As I write this in 2023, the publicly available data on the effectiveness of outfield shifts are sparse and indirect, but they still suggest that outfield positioning has probably had a bigger impact than infield shifts on offensive performance. Using Baseball Savant positioning data, Robert Arthur was able to compare seven teams that were not adjusting their outfield positioning in 2016 but had implemented shifts by 2020.23 Relevant BABIP dropped 10 points as a result.24

Arthur also uncovered evidence that outfielders were being positioned deeper starting in 2015 or earlier. Although BABIP on balls hit to them was roughly the same, right fielders were positioned four feet deeper in 2019 than they were in 2015, and left fielders were positioned seven feet deeper. In contrast, center fielders were positioned 12 feet deeper in 2020 than in 2015, and BABIP on balls hit into their territory dropped by an astounding 40 points.25

Overall, from 2015 to 2022, BABIP on fly balls and line drives hit to the outfield fell from .412 to .400, according to data from Baseball Savant. This was part of a larger decline since the beginning of the pitch-tracking era. Over the same period, BABIP on groundballs fell from .249 to .241. This smaller drop brought groundball BABIP in line with the first several years of the pitch-tracking era. See Figure 6 for the entire 2008–23 era.

 

 

CHANGES IN BATTING STRATEGY

In the face of increased shifts, many batters responded by attempting to hit the ball over them. There is no doubt that such a strategy increased the home run rate. According to FanGraphs, from 2015 to 2023, the MLB groundball rate fell from 45.3% to 42.9% while the fly ball rate rose from 33.8% to 37.2%, as demonstrated in Figure 7.

Those fly balls were also more productive, as their isolated power rose from .391 to .573. The increase was particularly pronounced when batters faced shifts. Against strategic and full shifts, batters had an average launch angle of 11.7 degrees in 2015. That launch angle rose to 12.7 degrees in 2016 and 13.4 in 2017. From 2018 to 2022, it fell below 14 degrees in just one season. When the defense was in a standard alignment, the average launch angle rose above 12 degrees just once, in 2023. In addition to lifting the ball more often when shifted, both left-handed and right-handed batters did more damage on balls in the air. The rate of home runs per fly ball, which never exceeded 11.4% between 2007 and 2014, rose as high as 15.3% in 2019, as demonstrated in Figure 8.

To demonstrate the benefits of lifting the ball more, Rob Mains looked at the 185 batters who made at least 350 plate appearances in both 2015 and 2016. He split them into deciles based on the year-over-year change in their groundball rate. Using Baseball Prospectus’s True Average (TAv) metric, which places all offensive production on a scale analogous to batting average, he found that players who lowered their groundball rate in 2016 performed better overall and those who hit more groundballs performed worse, although the difference was small.26

Batters adopted two tactics that led to the increased home run rate. The first tactic was pulling the ball more often, as seen in Figure 9.

 

 

Between 2013 and 2020, the pull rate of fly balls rose from 22.7% to 24.5%. It’s no secret that pulled fly balls are more dangerous. From 2008 to 2022, pulled fly balls and line drives ran a slash line of .612/.603/1.356, whereas fly balls and line drives hit to center and to the opposite field had a slash line of .388/.379/.640. Using the same method described earlier, Rob Mains discovered that players who pulled the ball more also improved their overall performance.27

The second tactic for increasing the home run rate was improving the quality of contact. The distinction between hard, medium, and soft contact shown in Figure 9 is based on Sports Info Solutions data. SIS uses a proprietary method to classify batted balls based on the type of batted ball, time in the air, and landing location combined.28

The rate of hard-hit balls topped 30% just once between 2007 and 2015, but it has done so in every year since 2016, as demonstrated in Figure 10. However, the topic at hand is batting average, rather than overall offensive performance. Because fly balls and popups have had a lower combined batting average than groundballs, the league’s shift away from groundballs and toward fly balls has depressed batting averages overall.

 

 

CONCLUSION

Given its immediate aftermath, the infield shift ban must be considered a qualified success. The 2023 MLB batting average increased by five points to .248. BABIP rose seven points to .297, and all four hit types increased in frequency. Right-handed hitters saw no decrease in batting average or BABIP, and left-handed hitters improved both their average and BABIP by 10 points. The 2023 figures were right in line with what would be expected if full shifts were replaced by partial ones.

Indeed, Russell Carleton calculated a correlation coefficient of .775 between the percentage of full shifts a left-handed batter faced in 2022 and the percentage of “strategic” shifts they faced in the first half of 2023. The corresponding figure for right-handed batters was 0.542.29 Carleton also noted that the overall performance of batters facing strategic shifts was similar to those reported in Table 1.

In 2023, both batting average and BABIP reached their highest marks since 2019, but BABIP saw a larger increase. The league’s .248 batting average was still the fifth-lowest mark of this century. If the Lords of Baseball want more drastic changes, they will probably need to consider other options. Restricting outfield positioning could have a real effect on both BABIP and batting average, but to the best of my knowledge there has been no serious consideration of this possibility. Any further changes would need to move beyond defensive positioning and address the effects of the strikeout epidemic. A discussion of these changes and what they might accomplish will come in the second half of this two-part study.30 

CHARLIE PAVITT has been a SABR member since 1983. His Statistical Baseball Research Bibliography is now integrated into SABR’s Baseball Index; his Sabermetric Research Literature Review is intended to be a complete survey of the literature and consistently gets updated. He is currently compiling sabermetric terms for a fourth edition of The Dickson Baseball Dictionary.

 

Acknowledgments

Thanks to Dick Cramer for writing suggestions, Pete Palmer for always reading what I write, Davy Andrews for supplying me with the Baseball Savant data used here, and Cliff Blau both for being a superb volunteer copy editor and fact checker and for informing me of Peter Morris’s reference to nineteenth-century shifting.

 

Notes

1 “MLB announces rule changes for 2023 season,” MLB.com, September 9, 2022, https://www.mlb.com/press-release/press-release-mlb-announces-rule-changes-for-2023-season

2 Matt Snyder, “MLB rule changes: What to know about the extreme shift ban, what defensive tricks are sill allowed,” CBS Sports, March 2, 2023, https://www.cbssports.com/mlb/news/mlb-rule-changes-what-to-know-about-the-extreme-shift-ban-what-defensive-tricks-are-still-allowed/

3 Kevin Skiver, “MLB infield shift rules, explained: How new restrictions, minimums & violations will impact 2023 games,” The Sporting News, March 30, 2023, https://www.sportingnews.com/us/mlb/news/mlb-infield-shift-rules-violation-2023/j5euqqru11cghxrgtayvzpdl

4 FanGraphs, https://www.fangraphs.com/leaders/major-league?pos=all&stats=bat&lg=al&lg=nl&qual=y&type=0&month=0&ind=0&team=0%2Css&startdate=&enddate=&pageitems=200&season1=1920&season=2022 This information is for 1920 through 2022.

5 Based on data mostly from Baseball Reference (https://www.baseball-reference.com/leagues/majors/bat.shtml) but with batting average on balls in play (BABIP) numbers from FanGraphs.

6 Despite the oddity of the season, I have included 2020 as it was similar to the two after it.

7 See https://commons.wikimedia.org/wiki/File:Cy_Williams_defensive_shift.jpg for a newspaper account from May 24 of that year.

8 Peter Morris, A Game of Inches, Vol. 1 (Chicago, Ivan R. Dee, 2006), 222. Thanks to Cliff Blau for informing me of this.

9 Seymour Siwoff, Steve Hirdt, Tom Hirdt, and Peter Hirdt, The 1991 Elias Baseball Analyst (New York: Simon and Schuster, 1991), 79–80.

10 Joe Rosales and Scott Spratt, “The Effectiveness of Full vs. Partial Shifts,” in The Hardball Times Baseball Annual 2016, prod. Paul Swydan (Fangraphs, 2016), 307–315.

11 Mark Simon, “Has the Shift Seen its Day?” Presented at the 2018 SABR Analytic Conference.

12 https://baseballsavant.mlb.com/visuals/team-positioning?teamId=111&venue=home&firstBase=0&shift=0&batSide=&season=2022

13 Russell A. Carleton, “The Mirror Told Me I Was Backward.” Baseball Prospectus, https://www.baseballprospectus.com/news/article/61566/baseball-therapy-the-mirror-told-me-i-was-backward/; Carleton, “The Shift that Happened in 2021,” Baseball Prospectus, https://www.baseballprospectus.com/news/article/71913/baseball-therapy-the-shift-that-happened-in-2021/; Carleton, “Shifting to the Right,” Baseball Prospectus, https://www.baseballprospectus.com/news/article/76073/shifting-to-the-right/

14 Russell A. Carleton, “The Walk Penalty and the Death of the Shift.” Baseball Prospectus, https://www.baseballprospectus.com/news/article/61143/walk-penalty-infield-kill-the-shift-mlb-defense/

15 Carleton, “The Mirror Told Me I was Backward.”

16 Carleton, “Why the Shift Works (Sometimes),” Baseball Prospectus, https://www.baseballprospectus.com/news/article/65133/baseball-therapy-why-the-shift-works-sometimes/

17 Carleton, “New Year, New Rules–Part 1,” Baseball Prospectus, https://www.baseballprospectus.com/news/article/65496/baseball-therapy-new-year-new-rules/

18 Carleton, “The Shift that Happened in 2021.”

19 Robert Arthur, “The League’s Defensive Positioning has Changed,” Baseball Prospectus, https://www.baseballprospectus.com/news/article/67237/moonshot-the-leagues-defensive-positioning-has-changed/

20 Arthur, “Better Defense is Costing MLB Thousands of Hits,” Baseball Prospectus, https://www.baseballprospectus.com/news/article/67362/moonshot-better-defense-is-costing-mlb-thousands-of-hits/

21 Brian Reiff, “The Effectiveness of Strategic Outfield Positioning,” Presented at 2019 SABR Analytics Conference.

22 Simon, “The Rise of Outfield Shifts,” Bill James Online, https://www.billjamesonline.com/the_rise_of_outfield_shifts/.

23 The Reds, Pirates, Marlins, Nationals, Rangers, Orioles, and Tigers.

24 Arthur, “Outfield Shifts are Shockingly Effective,” Baseball Prospectus, https://www.baseballprospectus.com/news/article/65713/moonshot-outfield-shifts-are-shockingly-effective/

25 Arthur, “The League’s Defensive Positioning has Changed.”

26 Mains, “New Year’s Resolutions: Ground-Ball Hitters, Baseball Prospectus, https://www.baseballprospectus.com/news/article/30932/flu-like-symptoms-new-years-resolutions-ground-ball-hitters/

27 Mains, “New Year’s Resolutions: Going the Other Way,” Baseball Prospectus, https://www.baseballprospectus.com/news/article/30914/flu-like-symptoms-new-years-resolutions-going-the-other-way/

28 Neil Weinberg, “Quality of Contact Stats,” FanGraphs, https://library.fangraphs.com/offense/quality-of-contact-stats/

29 Carleton, “The Afterlife of the Shift, Baseball Prospectus, https://www.baseballprospectus.com/news/article/83984/baseball-therapy-the-afterlife-of-the-shift/