The Good Outweighs the Bad with Pittsburgh’s Tyler Glasnow

Less than a month ago, the Pirates called up top prospect Jameson Taillon from the minor leagues, and slotted him into their struggling rotation. With Taillon now sidelined by shoulder fatigue, the Pirates have once again dipped into their minor-league repository. Today, they’ve called up yet another top-tier pitching prospect in Tyler Glasnow. Glasnow’s spent the past three months putting up sick-nasty numbers with the Pirates’ Triple-A affiliate. In 96 innings across 17 starts, he boasts a 1.78 ERA and 2.94 FIP. He’s struck out a remarkable 30% of batters faced this year, which is tops among qualified Triple-A hurlers. Triple-A hitters proved to be no match for his filthy fastball-curveball combination.

Glasnow’s mowed down minor-league hitters, but many are concerned that his lackluster command will prevent him from succeeding at the next level. That’s a big reason why the Pirates kept him in the minors as long as they did, and why they passed him over for Taillon when they needed a pitcher last month. As lead prospect analyst Eric Longenhagen noted in a recent chat, “His stuff is hellacious and pitchers with that body type often develop command late, but there’s a non-zero chance Glasnow never throws enough strikes to dominate.”

Glasnow’s lack of command shows up in the numbers, as well. He’s walked an alarming 14% of opposing batters this season, which is third-worst among qualified Triple-A pitchers (“trailing” only Henry Owens and Jorge Lopez). He walked a similarly concerning 11% between 2014 and 2015. I had the opportunity to play with some minor-league COMMANDf/x data a couple of years ago, and let’s just say the numbers didn’t paint Glasnow in a very favorable light. Of the prospects with whom I was familiar, his readings were easily among the worst in my sample. That data was from 2014, but seeing how his walk rates haven’t improved since then, it’s probably safe to conclude his command and control haven’t budged much either.

Despite the walks allowed, KATOH still sees Glasnow as one of the most promising young pitchers on the planet due to his gaudy strikeout rates. Heading into the year, my system pegged him for 9.5 WAR over the next six years, which placed him 13th overall and third among pitchers. His forecast has since ticked down to 7.8 WAR, largely due to his worsened walk rate. But his projection is still near-elite.

To put some faces to Glasnow’s statistical profile, let’s go ahead and generate some statistical comps for the 6-foot-7 righty. I calculated a weighted Mahalanobis Distance between Glasnow’s Triple-A performance this year and every Triple-A season since 1991 in which a pitcher recorded at least 350 batters faced. In the table below, you’ll find the 10 most similar seasons, ranked from most to least similar. In generating Glasnow’s comps, I only considered pitchers who cracked Baseball America’s top-100 list either before or after the season in question. This is intended to act as a proxy for “good stuff,” which Glasnow certainly has. The WAR totals refer to each player’s first six seasons in the major leagues. A lower “Mah Dist” reading indicates a closer comp.

Please note that the Mahalanobis analysis is separate from KATOH. KATOH relies on macro-level trends, rather than comps. The fates of a few statistically similar players shouldn’t be used to draw sweeping conclusions about a prospect’s future. For this reason, I recommend using a player’s KATOH forecast to assess his future potential. The comps give us some interesting names that sometimes feel spot-on, but they’re mostly just there for fun.

Glasnow’s command is iffy, and he’ll likely post higher-than-average walk rates in Pittsburgh — just as he did in the minor leagues. All else being equal, you’d prefer to have a pitcher that doesn’t push 15% with his walk rate. But all else isn’t equal with Glasnow. His ability to generate strikeouts, especially at such a young age, is a huge point in his favor. According to my math, the good far outstrips the bad in Glasnow’s case.

In the here and now, Glasnow should give the Pirates a nice little boost that could help keep them in the thick of the NL Wild Card race. Steamer calls for a 3.84 ERA from here on out, which would certainly be an upgrade over whomever he replaces in Pittsburgh’s rotation. Shifting innings away from Jeff Locke, Jon Niese and Chad Kuhl can only help matters. In the longer term, Glasnow has the chance to blossom into one of baseball’s best and most exciting pitchers.