Hitters Playing Through Injury Means Jack Squat

Dammit. For a few years, I followed an old study showing hitters who played through an injury would outperform their next season’s projections, especially in relation to power. Last offseason, I collected a list of 26 such hitters. When I went to compare this group’s projections to their actual performance, I found no overperformance and I’m not sure how I’ll value them going forward.

I thought the 2018 and previous numbers would match with the likes of Mookie Betts, Xander Bogaerts, and Matt Carpenter improving. Their gains weren’t enough to offset the losses by the likes of Dexter Fowler, Freddie Freeman, and Adam Jones. In the end, these hitters performed the same as their projection to a bit worse. Using weighed plate appearances, differences were exactly .000 except SLG and OPS which was -.001. The unweighted declines were closer to -.020 across the board but Pedroia weighed heavily on those values.

I thought something was off, so I cut and diced the 26-sample set by age, known injuries going into the season (e.g. Bird and Murphy) and weighing the plate appearances differently. Nothing made a difference.

I used to personally adjust my projections up a bit for these hitters since the projections didn’t know about the jump. I’m not going to make any whole scale adjustments with this season’s list. If anything, I’ll keep the 2018 list in mind and may make small adjustments on a case-by-case basis. Until then, it’s off to some more offseason mining for hidden gems.