How Rules Changes in 1920 Affected Home Runs

This article was written by David Vincent

This article was published in the 2006 Baseball Research Journal

The home run was not a major part of a batter’s arsenal in the 19th century. In fact, at the end of the century Roger Connor was the career leader in home runs with 138, and only seven players had smashed 100 or more four-baggers. During the first two decades of the new century, an era commonly referred to as the Deadball Era, home run production by batters decreased from the general production rate of the 19th century.

In measuring how the four-bagger has become more prevalent in the game though the years, raw counting totals will not suffice. It is easy to state that 40 homers were hit in the initial year of the National League in 1876, and 238 were clouted in 1883 in the major leagues by batters in the National League and the American Association, which started as a major league in 1882. At first glance, this looks as if homers were being hit at six times the rate in 1883 as in 1876. However, these numbers do not take into account the fact that more games were played in 1883 than in 1876, and by adding some context to the raw counting totals, we can get a better idea of the real difference between these two seasons (and in fact any two years).

The method employed here is a “home run production rate.” It is calculated not by dividing homers by at-bats, similar to batting average, but by calculating how many circuit drives were hit per 500 plate appearances. A straight calculation of homers divided by plate appearances would provide numbers not readily understandable by the reader. In 1876 the 40 homers were hit in over 20,400 plate appearances. As a percentage (.196%), this number is hard to understand and hard to quantify as good or bad. Similarly, the 238 home runs hit in 1883 were clouted in approximately 60,000 plate appearances. This result is 0.397%, which is also hard to quantify.

The 500 plate appearance standard was chosen because the official minimum performance standard for individual batting championships as listed in rule 10.23(a) is 3.1 plate appearances times the number of games scheduled for each team.1 Thus, in the 162-game schedule, 502 plate appearances is the minimum, but that was rounded here to 500 for simplicity. The home run production rate will generate numbers that can be compared to other numbers that have some context for the reader, such as a 30-homer season by a batter.

Look at the rates in the two previously discussed years as home runs per 500 plate appearances. In 1876, batters hit one homer for every 500 plate appearances while in 1883, batters hit two four-baggers for every 500 plate appearances. Thus 1883 batters were not hitting circuit drives six times more frequently than their 1876 brethren, as might be inferred by the raw totals, but rather only twice as often.

Figure 1 shows the yearly production rate for each season from 1876 through 1919, the end of the Deadball Era. It is clear from the figure that the rate during the start of the 20th century was lower than the general rate in the previous century. This drop in home run production in the Deadball Era can be attributed to a number of factors, a discussion that is beyond the scope of this article.


Figure 1: Home Run Production Rate (1876–1919)

Figure 1 . Home Run Production Rate (1876–1919) (DAVID VINCENT)

(Click image to enlarge)


Before the start of the 1920 season, changes were made to the game that had a great effect on the balance between offense and defense. New playing rules were put into place that affected home runs and, in addition, the ball itself changed.

The first of three rules changes stated that fly balls hit over the fence along the left- and right-field lines would be judged fair or foul according to where the ball passed the fence rather than where it landed. The previous version of the rule had seemed reasonable and helpful to the umpires: they would call a fly ball fair or foul after watching it land, since judging the flight of the ball without a pole at the intersection of the line and the wall could be difficult, and there were no poles on the lines at this time.

This rule changed a few times during the 1920s. On June 25, 1920, with fewer than 60 games played by most teams under the new statute, the rule reverted to the 1919 version, which stated, “The umpire shall judge it fair or foul according to where it disappears from view.” Before the 1928 season the rule again became “where the ball crosses the fence.” National League president John Heydler stated that trying to determine where the ball actually landed was often very difficult. However, this applied only to balls crossing the barrier that indicated the edge of the playing field and that landed in the seating area. If a ball flew completely out of the park, it was to be judged not where it flew over the inner barrier but where it crossed the outer barrier. Therefore there were two different interpretations of the rule, which depended on how far the ball traveled before deciding the proper interpretation to use.

National League president Heydler held a meeting with all league umpires in his New York office on August 5, 1928. Part of the discussion regarded the double interpretation of judging a fly to be fair or foul. The umpires favored one rule for both situations, to call the ball fair if it crossed the inner barrier in fair territory regardless of the flight of the ball after that. Since most of the poles recently constructed to help umpires judge fly balls were not tall enough to allow a single interpretation of the rule as requested by the arbiters, Heydler decided not to change the rule interpretation during the 1928 season.

However, the league adopted a new rule for the 1929 season regarding those poles. It stated that a pole must be constructed at least 25 feet above the outer barrier to aid the umpires in calling balls fair or foul. The taller poles were constructed on either the top of the grandstand roof or the outer fence of the park, and the umpires got their wish for a single interpretation of the rule concerning calling flies fair or foul in 1929 to the “where the ball leaves the playing field” version. The American League continued to use the double interpretation of the rule through 1930.

The second change in the playing rules for 1920 concerned game-ending hits. Previously, if a batter hit a ball over the fence to end a game, he received credit only for enough bases on that hit to allow the winning run to score. In other words, if the game was tied and a runner was on second base, a ball hit out of the park became a double, since, when the runner on second scored, the game ended. The new rule allowed the batter and all runners to score on such game-ending hits, and the batter received credit for a home run.

There are 43 known instances of these game-ending hits before 1920. Since the rules of the day were clear about these hits not being home runs, it is incorrect to state that the players “lost” a homer. They were never home runs under the play- ing rules. Jimmy Collins of the Boston Beaneaters (later Braves) hit two of these game-ending blows, one in 1899 and one in 1900, and Sherry Magee of the Philadelphia Phillies hit two, in 1906 and 1914. Collins and Magee are the only batters who had two of these game-ending hits. The Boston Braves had the most as a team with nine, and the New York Giants hit eight of them.

Major League Baseball formed a special rules committee in 1968 to make decisions regarding record keeping in the early days of professional baseball. The committee attempted to make the old statistics consistent with modern scoring rules, and one of its rulings changed the known pre-1920 game-ending hits to home runs. Note that on July 8, 1918, Babe Ruth hit one of these game-enders and received credit for a triple at the time. Thus the committee’s ill-advised ruling changed the record for most career home runs from 714 to 715. To make things worse, as part of this ruling the committee had to change the final score of the affected ball games and the pitching records of the hurlers who surrendered the hits.

When the committee announced this decision, many sports reporters wrote stories regarding the change in Ruth’s record. Leonard Koppett, writing in the New York Times on April 27, 1969, stated: “For several years now, Willie Mays has been gradually closing in on Babe Ruth’s career total of 714 home runs, one of the most hallowed statistics of all sports lore. Well, here’s a shock for Willie and all his fans: the Babe just gained ground on him.” Koppett discussed the entire computerization project which produced the first comprehensive baseball record book, published in 1969. He was generally complimentary about the project and the records committee; however, he ended his story with: “But it just lends support to those who believe that Ruth was the supreme slugger, the giant among giants. Here he is, after all, adding to his total 34 years after he played his last game.”

Koppett’s remarks helped focus attention on the ruling concerning game-ending hits. If the Babe had not been on the list, the ruling might have remained in place. However, changing the most recognizable statistic in all of sports generated a lot of negative feedback. Therefore, in May 1969 the special committee reversed itself on this one ruling, thus leaving the Babe’s home run record intact at 714. It should be stated again that these batters did not lose home runs at this time because those hits were never homers according to the playing rules. The initial decision by the special committee granted something to the batters in conflict with the playing rules at the time of the event, and the reversal of this decision, although made for the wrong reason, achieved the correct status for these hits.

On July 11, 1920, the Boston Braves were tied with the Reds, 3–3, after eight innings in Cincinnati. In the bottom of the ninth, the Reds had Hod Eller running at second base and Morrie Rath at first when Jake Daubert came to the plate with two out. Daubert hit Hugh McQuillan’s 1–1 pitch to center field, where it bounced once and hopped into the bleachers. Under the new rule on game-ending hits passed before this season, Daubert got credit for a three-run home run to win the game, 6–3, thus becoming the first batter to receive credit for a homer because of the rule change. (Through 1930, a ball which landed in fair territory and then bounced out of play was a home run.) Four days later, the St. Louis Browns and the New York Yankees were tied, 10–10, after 10 innings at the Polo Grounds in New York. In the bottom of the 11th inning, with Aaron Ward the runner at second base and Wally Pipp running at first base, Babe Ruth came to bat with no one out. Ruth hit the ball onto the right-field roof for a three-run, game-ending home run.

This was the Babe’s 29th of the season, tying his record set the previous year, and the first American League home run under the new rule. These were the only two game-ending home runs under the new rule in 1920. Ruth is the only batter on the list of game-ending hits under the old rules who hit a game-ending homer under the new rules that would not have qualified as a homer before 1920.

The third playing rule that changed for the 1920 season had a huge effect on hitting. It stated that the spitball and other unorthodox deliveries were outlawed. In other words, hurlers were no longer allowed to apply substances to the ball or scar its surface before pitching it, which included using rosin. Here is the wording agreed on at the meeting in February 1920:

At no time during the progress of the game shall the pitcher be allowed to (1) apply a foreign substance of any kind to the ball; (2) expectorate either on the ball or his glove; (3) to rub the ball on his glove, person or clothing; or (4) to deface the ball in any manner or to deliver what is called the “shine” ball, “spit ball,” mud ball or emery ball. For a violation of any provision of this rule the pitcher shall be ordered from the game and be barred from participation in any championship contest for a period of ten days.

This change led to an increase in offense in 1920 and the following seasons because hurlers were no longer allowed to throw a “trick” or “freak” pitch to fool the batter. However, teams registered a group of pitchers already in the majors with the league presidents, and those hurlers could continue throwing the spitball (but not any other banned pitch) through the 1920 season only. After that year, all use of the spitball would be abolished. However, at a meeting the following December, the leagues extended the rule concerning these registered spitballers to allow them to continue throwing that pitch until they retired. Burleigh Grimes, who pitched until 1934, became the last of these grandfathered hurlers still in the major leagues.

These outlawed pitches were common during the Deadball Era. Applying a substance to the ball or scuffing it would cause it to curve, sometimes in an unusual way. Pitchers who did not have a good curveball liked these freak pitches because throw- ing one gave them a kind of breaking ball to use as a part of their arsenal. However, the unusual flight of these pitches meant that the hurler often had no control over where the pitch went, and sometimes that meant directly at the batter.

Because of the fear of a scuffed ball veering in toward a batter’s head and causing serious injury, starting in 1920 umpires threw out any scuffed or discolored ball and placed a new ball into play immediately. Prior to this time, one baseball might be used for the entire contest regardless of its condition. With the elimination of the “freak” pitches and cleaner, easier-to-see balls in use, the batters had less fear of being injured by a baseball striking them. Therefore, they could stand in the batter’s box with more confidence and have a better chance of hitting the ball long and hard.

The fact that balls hit into the stands were usually kept by the fans and not returned to the field became another consideration in ball replacement during a game. As the number of homers hit out of the park increased, so did the need to use a new baseball during the game, as each home run ball would be unavailable to the players, thus providing another situation in which a new, clean baseball replaced a used ball.

The last change in 1920 involved the baseball itself. Historians generally refer to the baseball period starting in 1920 as the “Lively ball era,” or a similar appellation. Starting that season, the baseball seemed to travel a lot farther off the bat, something that was discussed at great length and described with great negativity at the time.

Many older baseball men decried the “rabbit” ball and home run sluggers such as Babe Ruth. They were said to be not playing the game the way it was meant to be played and ruining the sport. Of course, the fact that fans were coming to the ball- parks in record numbers was conveniently ignored by these detractors.

At the time, each league used a ball from a different manufacturer. The A.G. Spalding Company manufactured the National League baseball while Reach & Company made the sphere for the junior circuit. They were all made to the same specifications, the only difference being that the stitching on the cover of the National League ball had two colors, red and blue, while the American League ball had red yarn holding the outer cover on the ball.

The league presidents and representatives of the manufacturers all agreed during the 1921 season that no changes had been made to the specifications of the baseball. The primary theory discussed at the time as the cause of the “rabbit” ball was the fact that during World War I the government took the best quality wool for its own use, and commercial enterprises, such as Reach and Spalding, had to use wool of lower quality than they had previously used. With the end of the war, importers brought better quality wool from Australia into the United States. The yarn made from this wool was of better quality and was able to be wound tighter around the core of the baseball by the machines that completed that part of the process. The tighter winding was a result of the better-quality yarn, not a change to the machines, and created a slightly harder, more elastic ball—one that batters could hit farther than the old baseball.

The war had also depleted the ranks of workers in baseball factories, just as it had on the ball field. With new, inexperienced workers in the factories, the quality of the product was sure to deteriorate until the veteran laborers returned after the end of the war. Although machines performed the first part of the manufacturing process, workers hand-stitched the cover on the ball, and the post-war covers were probably more uniform in their quality than those used at the end of the Deadball Era. What was the effect of these changes? The home run production rate soared in the 1920s, as shown in Figure 2.


Figure 2: Home Run Production Rate (1920–1930)

Figure 2: Home Run Production Rate (1920–1930) (DAVID VINCENT)

(Click image to enlarge)


Whereas the highest rate before this time had been the 4.8 homers per 500 plate appearances in 1894, the production rate in eight of the 11 years in the chart was equal to or higher than the 1894 rate. Only 1920 (the start of the Lively ball era) and 1926 had lower rates than 1894.

There have been other rules changes that have affected offense and home runs in the history of baseball. However, none of the changes have had the impact of the set of modifications that took place before the 1920 season.

DAVID VINCENT, called the “Sultan of Swat Stats” by ESPN, is the recognized authority on the history of the home run and was presented with the SABR’s highest honor, the Bob Davids Award, in 1999. This article is excerpted from Home Run: The Definitive History of Baseball’s Ultimate Weapon, published in March 2007 by Potomac Books.



1 Major League Baseball revised section 10 of the Official Rules before the 2007 season. Under the new organization of that section, rule 10.23 was renumbered as 10.22.

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