Playing shortstop is a young man’s game. The list of top-tier shortstops age 25 and under in the game right now is so extensive that it’s impossible to pare down to a quick three- or four-name list without leaving off a potential future MVP. If you’re interested in fawning over those names and debating who among them is the most valuable, I’d recommend keeping an eye on Dave Cameron’s trade-value series this week. But right now, I want to talk about a guy who suddenly looks like a grizzled veteran next to the new wave of shortstop talent: 26-year-old Didi Gregorius.
Over the past month, Gregorius has been the most productive shortstop at the plate. Go back a bit further and you’ll find that, after struggling in the first month of the season, he’s posted an impressive 131 wRC+ since May 8th. On the season as a whole, though, his 109 wRC+ ranks a respectable, if uninspiring, 11th among shortstops behind eight (!) members of that 25-and-under age bracket. There’s no argument to be made that Gregorius is anything like the best shortstop in the game right now, but he is in the midst both of a remarkable stretch and also his finest overall season at the plate. He also has three more years of team control remaining, which makes it worth investigating to what extent this Gregorius breakout is for real.
The most obvious and, perhaps, the most fun part of Gregorius’ breakout has been his power surge. He’s recorded five home runs in his last 11 games, which has helped boost his ISO to a career high .169. He’s hardly the only shortstop to grow into power after a few seasons in the majors: Brandon Crawford and Zack Cozart followed a similar trajectory. Gregorius’ power is aided by the fact that he’s a left-handed hitter who gets to play half his games in Yankee Stadium. Unsurprisingly, his home/road power split is rather stark:.210 ISO at home, .132 on the road. If I were a team interested in acquiring Gregorius, this would be a concern, but unless the Yankees are planning to move anytime soon, they should feel comfortable accepting that Gregorius possesses the ability to make the most of his home ball park.
There is something about Gergorius’ newfound power, however, which necessitates pouring a bit of cold water on the idea that he’s tapped into a new ability which will help elevate him to a new level. Check out his season-by-season ISO:

Yes, Gregorius is hitting for more power and that’s a great thing, but he’s not alone. Power is up across the league and, rather than pulling ahead of the pack, Gregorius is merely keeping pace with league average. (Gregorius recorded only 21 plate appearances in that 2012 season, so the relevant start date for his ISO comparisons begins in 2013.) The power increase among shortstops is even more stark than the league-wide trend. Since 2014, the average ISO for shortstops across the league has risen from .113 to .151 — nearly forty points! So, yes, the new power is fun to watch, but it’s not going to alter substantially Gregorius’ standing in the league.
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