Projection Altering Hitter Injuries

I’ve had a semi-fixation on hitters playing through injuries and how the diminished production could hamper the next season’s projection. At first, I found some correlation. Then, I didn’t. One possible answer to there being no bounceback is that the injury becomes chronic and the hitter never improves. Or the dataset could be too small.

I want to dive further into the subject, but the information around injuries is sketchy at best. Most of the time, there are no usable details. The lack of an answer means that I should stop coming back to the subject but I’m stubborn.

Very.

I’m going to go through this past season’s hitters. The dive has a couple of goals. One is to create a better dataset for future reference. The second is to understand why some hitters may have struggled when creating a profile. And just maybe, I’ll find out if I can put to rest the notion that hitters who played through injuries are under projected.

After diving through the material, I removed some players (e.g. Aaron Judge) from the list mainly because the media theorized injuries were behind the struggles. I wanted facts from the player or team. In all, I ended up with 30 hitters and here they are grouped into two main categories. When possible, I included the injury’s approximate date and the hitter’s before and after OPS.

First off all, I found five hitters useless for this analysis. The reference to Roberto Pérez’s injury was too vague to get any kind of read on it. I just don’t care about David Bote and Daniel Descalso. Finally, Freddie Freeman and Anthony Rizzo had their injuries too late in the season to really matter.

I’ll start with the 20 who had a defined in-season injury date.

2019 Hitters Who Played Through An In-Season Injury
Name Injury Location Injury Date OPS before OPS after Difference
Cody Bellinger Shoulder 05-06 1.367 .950 -.417
Domingo Santana Elbow 07-23 .814 .484 -.330
Hunter Renfroe Ankle & Elbow 06-23 .936 .620 -.316
Rhys Hoskins Hand 08-14 .869 .671 -.198
Matt Chapman Ankle/Knee 07-19 .918 .739 -.179
C.J. Cron Thumb 06-15 .865 .695 -.170
Khris Davis Hip 05-05 .784 .640 -.144
Alex Verdugo Back 05-15 .913 .771 -.142
Mike Trout Foot 08-09 1.107 .972 -.135
Javier Báez Heal 06-01 .924 .797 -.127
Marcell Ozuna Shoulder 06-25 .847 .739 -.108
Justin Smoak Quad 06-28 .787 .706 -.081
Mike Moustakas Finger 04-16 .899 .836 -.063
Kris Bryant Knee 07-22 .930 .876 -.054
Nolan Arenado Toe 06-16 .956 .968 .012
Tommy Pham Hand 08-10 .812 .834 .022
Yadier Molina Finger 05-31 .690 .727 .037
Lorenzo Cain Thumb 07-25 .671 .726 .055
Max Kepler Knee 05-23 .792 .884 .092
Nelson Cruz Wrist 05-12 .862 1.096 .234
Average -.101
Median -.118

The results are as expected. On average, the injury hampered the hitter’s performance by about 100 points of OPS. The performance didn’t always get worse with 30% (six) experiencing a performance increase. Remember, it has not been determined if a bounceback can be expected. They could continue to struggle.

The final five hitters where basically hurt to start the season so there is no before and after dates.

2019 Hitters Who Played Through A Preseason Injury
Name Injury Location Notes
Brandon Nimmo Neck .851 before to .536 to IL to .995
Ramón Laureano Shin Injured in the first series, production climbed, then the IL, came back strong
Daniel Murphy Finger Not sure he got healthy.
Trea Turner Finger IL to start the season
Gregory Polanco Shoulder Was never healthy and needed surgery

So what to do with this information? For any actionable and impactful information, little. I’ll wait until the 2020 season ends to update the projected versus actual results and see if anything exists. While I’ve collected the general lists over the past two seasons, I haven’t dived into each injury as I did above. Maybe if I get bored, I can make tables like those above. It’s just time-consuming. I am though designating these hitters on my draft board and if there is a tie-breaker, I’ll pick the one who played through injury. Old ideas are tough to let go.

We hoped you liked reading Projection Altering Hitter Injuries by Jeff Zimmerman!

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Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first two seasons in Tout Wars, he's won the H2H league and mixed auction league. Follow him on Twitter @jeffwzimmerman.

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