Ellsbury’s Ankle Injury: Changes In Performance This Season and Next

Last night, Jacoby Ellsbury had three plate appearances in his return back from a fractured foot. He had a hit and a walk after missing just 20 days. I decided to go back and look at players who fractured their foot and how they performed after returning.

With a sample size of one game under his belt, Ellsbury looks great and he feels pretty good (source)

“Yeah it was a nice game back,” Ellsbury said. “I’m definitely excited about it. I felt pretty good out there.”

Great, but how have others hit over extended periods of times when returning from a fractured foot. I went back to 2002 and found 23 batters* who fractured a foot. On the average, they spent 49 day (37 median) on the DL. Here is how they performed after returning.

Notes: I collected four sets of data. The year before the injury, the year after the injury and in the year of the injury, before the DL stint and after it. I weighted each change in stats by the plate appearances’ harmonic mean. Finally, the same group of players may not have been used in each comparison. For example, it may have been the player’s rookie season when they got hurt (no season before for comparison) or the player ended the season on the DL (no in season after DL for comparison).

	PA	SB/PA	AVG	OBP	SLG	ISO
Season before to season after	5345	0.0%	0.002	0.000	0.022	0.019
In season, after compared to before	1948	-0.1%	-0.003	-0.007	-0.004	-0.001
Season before to in-season after	3718	2.3%	-0.002	-0.005	0.013	0.015
In season before to season after	3842	2.7%	0.004	0.002	0.014	0.009

So, here is what can be expected of Ellsbury:

• He should not see any effects in production next season (year before to year after). The one interesting note is an increase in ISO. I am not sure where this comes from. I thought the increase my be from players increasing in power because of their age. Again effects could explain some since the average age (weighted to plate appearances) was 29.6-years-old. Also, the player may have been trying to play through the injury for a while and suppressed their pre-DL stats. Otherwise, I can’t exactly explain this disconnect.

• For the rest of this season, he should expect a decrease in production with each AVG, OBP and SLG down. Also remember, this group of players saw a huge jump in power the next year, so their true power may have been dampened even more.

• The final two comparison agree with the other two observations. After returning from DL, the players performed worst, but once he had an off season to rest, they were fine.

• I decided to run one more data set and just look at those players (14 total) who spent 40 or less days on the DL to see if being rushed back had any affect on the in season comparison. None at all, basically because it was the same players being examined previous for in season stats. If I looked at 30 days or less (9 players), the numbers remain the same.

Ellsbury will probably not perform up to his 2013 pre-injury levels, but the decline in production is not nearly as bad if he hurt his back. I see no reason for the Red Sox not to use him in the post season and most important for fantasy owners, he should see no effects from the injured ankle next season.
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* Charlie Blackmon, Francisco Cervelli, Adam Rosales, Nate Schierholtz, Emmanuel Burriss, Jorge Posada, Juan Uribe, Travis Hafner, Jerry Hairston, Ryan Church, Shawn Green, Frank Thomas, Khalil Greene, Larry Bigbie, Torii Hunter, Ian Kinsler, Adam Jones, Austin Kearns, Kenji Johjima, Reed Johnson, Cody Ross, Michael Martinez, Logan Forsythe,