Watson: Testing the lasting effects of concussions in baseball

From SABR member Owen Watson at FanGraphs on February 18, 2015:

Pitchers are expected to lose command after Tommy John surgeries. Prolific base stealers coming back from hamstring injuries are expected to take it slow for a week or two before regularly getting the green light on the basepaths. A broken finger for a slugger is blamed for the loss of power; a blister for a pitcher might mean a loss of feel on their breaking ball. What is not well publicized, however, is how a player recovers from and reacts to returning from a concussion. For an injury that has been talked about in the media so often in the last few years, we know very little about the actual long-term, statistical impacts that concussions have on players that experience them.

Players often talk about being “in a fog” for some time after suffering a concussion – often even after they return to play. The act of hitting is a mechanism that involves identifying, reacting, and deciding on a course of action within half a second. With that in mind, I wondered: do concussions change the quality of a batter’s eye and discipline at the plate? Do brain injuries add milliseconds to those individual steps? Even though each injury is different, do varying lengths of disabled list stints due to concussions change a player’s performance on the field after they return? The most direct route to answering those questions might be studying the impact of concussions on strikeout and walk rates.

To start with, I’ve pulled data for all of the position players that went on the DL due to a concussion from the start of 2011 to the end of 2013.

Read the full article here: http://www.fangraphs.com/blogs/the-lasting-effect-of-concussions/

Originally published: February 18, 2015. Last Updated: February 18, 2015.