Graterol was having as good a season as any starting pitcher in the Southern League before hitting the IL with a shoulder impingement in May. He worked to a sub-2.00 ERA across nine starts, striking out more than 20-percent of hitters despite a walk rate that has ticked up a bit since moving to Double-A. Minnesota’s top pitching prospect was named an all-star at mid-season despite being unable to participate in the game.
It’s all about power for the strong righty, who sits in the upper-90s and regularly touches 100 mph with his fastball. It’s an explosive, heavy pitch with bowling ball sink, racking up more than 50-percent of balls in play on the ground so far in 2019. Graterol prevents walks fairly well for such a young hard thrower, with command that grades behind his present control. He’ll never have to be too fine with this type of velocity, able to blow hitters away enough to profile as a starter even with command that likely won’t ever be better than a 40/45-grade attribute. His primary off-speed is a hard slider, coming in at 88-to-91 mph with cut-like shape. It flashes as a no-doubt 60/70-grade hammer when there’s two-plane action, though he often overthrows it with limited depth. Though a 8.69 K/9 is certainly good, two double-plus pitches would likely miss more bats if Graterol was able to change speeds more. Everything is hard, and though his upper-80s changeup shows promise–flashing the potential to be an above-average pitch playing off dominant velocity–it isn’t a big part of his pitch mix now.
Graterol is still just 20-years-old, so there’s time to project up on the parts of his game that still need some fine tuning. The ingredients for a front-of-the-rotation starter are here, with the chance to pitch with average control and two 70-grade pitches at maturity. His fastball command and changeup will need to improve to reach that ceiling; Graterol could produce like a mid-rotation piece even with these two pitches, and if durability becomes an issue such that he needs a fallback, the stuff is easily here to be a force in a bullpen role. Given his injury issues this year, a contending Twins team might be tempted to fast-track Graterol as a reliever down the stretch, even if they ultimately ease him back into starting.