Evaluating Didi Gregorius since his return to the Yankees from the IL

Didi Gregorius has been back with the Yankees for just about three weeks after recovering from offseason Tommy John surgery, and not surprisingly, it is taking some time for the shortstop to shake off the lingering rust.

After Wednesday’s win against the Blue Jays, Gregorius headed across the pond with an OPS of .685 through 56 plate appearances, obviously far below his mark of .829 last year. Of course, collecting five hits in his last nine at-bats would suggest that the layer of rust is already being removed, and 15 games is a very, very small sample size, but nevertheless, let’s look at what might be causing Gregorius’ slow start, other than him likely needing time to get back in the swing of things.

What’s particularly telling about Gregorius struggling to find his stride is the at-bats he has been putting up at the plate. Gregorius’ strikeout rate sits at 17.9 percent compared to 12.1 last season, while his walk rate has dropped from 8.4 to 3.6 percent, his lowest mark since the 2016 season. This is uncharacteristic for a hitter of Gregorius’ caliber, especially when considering how the shortstop ranked in the top 10 percent in baseball in strikeout rate in 2017 and 2018, part of his ever-increasing value as a hitter since he came to the Bronx.

Given that recent history, we should be optimistic about Gregorius turning it around and producing like he has in years past. But is there something more to his start? Are opposing pitchers looking to attack Gregorius in a different way? Looking at how often Gregorius has seen certain pitches so far this season, we might be able to pull back that curtain a bit:

Upon first glance, it’s clear that Gregorius is seeing the least amount of fastballs in his career so far this year, and more breaking balls and offspeed pitches than ever. Again, this isn’t even a full month of data, but given how Gregorius adjusted to fastballs last year, this could be teams’ new game plan against him. Gregorius saw his hard hit percentage increase by 10 percent from 2017 to 2018 (rising from 24.1 to 34.1 percent), so opposing pitchers might be wary of showing him too much heat.

Given how Gregorius performed against fastballs last season, could he be hunting for the heater this year, looking to do damage? Looking at his chase percentage against fastballs, it looks like that might be the case. Gregorius may be anxious to pounce on a pitch that he’s seeing less than ever before, and expanding his zone as a result.

Gregorius’ strikeout percentage was on a steady decline from 2014 to 2018, and he has shown an ability to make adjustments at the plate in the past and continue to improve as a hitter, so it shouldn’t be a surprise if this spike in chase percentage levels off soon. Gregorius’ xSLG percentage on fastballs this season is at .310, almost 100 points below last year’s mark and currently the lowest mark of his career, but again, he’s been known to make adjustments. Wednesday’s game might have already been a glimpse at that, as Gregorius worked a 3-2 count and belted a high fastball for a home run into the Yankees’ bullpen.

Hopefully the Yankees and Gregorius see more of this in the near-future. Given his career trajectory and how he’s looked over the last few games, nobody should be surprised if that’s exactly what happens.