Jack Leiter’s Fastball Exemplifies His Talent
This is Justin’s first piece as a FanGraphs contributor. Justin has always been a baseball fan and a writer, but it wasn’t until Hyun Jin Ryu began dominating in 2019 that he started to fuse those interests together. He’s written for a few places since then, including Prospects365 and Dodgers Digest, and is now hoping to pester the good people of FanGraphs with his deep-dives into niche topics. Outside of the baseball blogosphere, he’s a student at Washington University in St. Louis.
Jack Leiter has been outstanding. So far this college baseball season, the sophomore from Vanderbilt University is sporting a minuscule 0.25 ERA in 36 innings pitched. He’s struck out 59 batters. Oh, and fun fact: He had a no-hit streak that lasted 20 innings. That’s largely thanks to a masterful no-hitter against South Carolina on March 21, during which he fanned 16 batters and allowed just a single walk. In his next start, he had seven no-hit innings going against Missouri but was pulled due to concerns over his ballooning pitch count.
At this point, to call Leiter outstanding might even be an understatement. Of course, the ERA seems unsustainable, and it wouldn’t be surprising if the right-hander runs into a bad day – it’s a volatile sport, after all. But regardless of what happens in the future, he’s already made a lasting impression on fans and scouts. In the months leading up to the college baseball season, however, Leiter was at times overshadowed by teammate and fellow pitcher Kumar Rocker. And though Leiter was obviously well-regarded, his placement on public draft boards ranged. He was (and still is) No. 1 on our draft board, while MLB.com placed Rocker first and Leiter sixth in a ranking published in mid-December and Prospects Live featured Rocker first and Leiter fifth in their own mock draft published in January. Kiley McDaniel had Leiter second on his February board, ahead of Rocker, and noted that ranking Leiter above Rocker is “the consensus view after they’ve each made their first start of the season.”
There’s no doubt that Jack Leiter is good. However, it can be tricky to evaluate him because some of the standard metrics undersell his greatness. For example, let’s consider his four-seam fastball. It averaged around 92 mph last season, a mark that hardly stood out. He’s bumped it up to 93-94 mph this season, and he does top out at 98, but it’s possible to have overlooked him in favor of more eye-catching flamethrowers. His raw spin rates are between 2200 and 2400 rpm, a range that would appear light-blue if displayed on a Baseball Savant page. You might have expected more from a top pitching prospect, and that’s understandable. Read the rest of this entry »