Jacob Lindgren, this year's second round draft pick, has been about as unhittable as it gets in his first two months as a professional. After agreeing to a contract on June 14th, the 21-year-old lefty reliever has breezed through four levels of the minors, posting a 0.96 ERA and striking out 51% of opposing hitters along the way. In addition to his on-field performance, all scouts agree that his stuff -- especially his slider -- is absolutely filthy. All things considered, Lindgren would almost certainly be better than both of the team's current lefties, David Huff and Rich Hill, meaning there's a very good chance he'll be summoned to the majors in the next couple of weeks.
Lindgren's minor league numbers have been great, but pitching in the big leagues is an entirely different animal. The hitters are more discerning at the plate and are much more likely to capitalize on mistake pitches. As a result, dominant minor league numbers don't always carry over to the big leagues. Take Dan Runzler, for example, who was my top comp for Lindgren when he was drafted based on PITCHf/x and scouting reports. Runzler put up a filthy 0.76 ERA and 36% K% in the minors in 2009, but went on to throw just 72 innings in the majors before being exiled to Japan last month.
Runzler was great back in 2009, but Lindgren's been another level of excellent, so it might be more useful to look at what became of similarly dominant minor league pitchers who made the leap to the big leagues. Since 2006, there have been 63 minor league relievers who have thrown at least 20 innings and struck out at least 40% of opposing batters. Most of these seasons took place entirely in the lowest levels of the minors, but a few of these pitchers went on to pitch in the big leagues that same year. Here's a look at those who threw at least 10 big league innings.
Not all of these pitchers lit the world on fire upon reaching the majors, but those most similar to Lindgren did. The few that did struggle were righties in their late 20's, who had been kicking around the minors for a few years. Guys like Edwar Ramirez, Jason Bulger, and Winston Abreu don't have much in common with Lindgren, but similar pitchers in terms of age and handedness -- Kevin Siegrist, Antonio Bastardo, and Sean Doolittle --fared very well.
As encouraging as this list seems, there's still reason to believe these comps are selling Lindgren a little short. Striking out half of the batters you face is a great way to keep runs off the board, but Lindgren doesn't stop there. He also had the second highest ground ball rate of all of D-1 college pitchers before joining the Yankees, and holds a ridiculous 86% (!) clip on 29 balls in play. This further contributes to Lindgren's dominance, as grounders generally don't do much damage -- MLB hitters average 35 wRC+ on grounders, compared to a 134 wRC+ for balls hit in the air.
Lindgren's something of a rare breed in that he generates both strikeouts and grounders at extreme rates. In that regard, he's very similar to pitchers like Andrew Miller, David Robertson, and Dellin Betances, who happen to be three of the top bullpen arms in all of baseball. Based on what we've seen so far, there's little reason to believe Lindgren won't be just as successful; and even if he's not quite there yet, he's ready to step in and help the Yankee bullpen right now. Hopefully he gets the chance to show what he can do sooner rather than later.