Tony Gonsolin has taken an atypical route to becoming a major league starter. As a two-way player at St. Mary’s College of California, Gonsolin primarily played in the outfield and pitched in relief. He was a senior sign, going to the Dodgers in the ninth round of the 2016 amateur draft. His offensive statistics were arguably more impressive than his pitching, but Dodgers thought he would work better on the mound than in the outfield.
For his first year and a half in professional baseball, Gonsolin continued to pitch out of the bullpen. During that time, he maintained a 4.10 ERA over 101 innings spread through rookie league to High-A. Going into the 2018 season, the Dodgers put him into the High-A starting rotation.
It’s not often that low-level prospect puts together average results as a reliever and then thrives as a starter. The Dodgers, however, were impressed by his repertoire which features four solid offerings: four seamer, split-finger, slider, and curveball. In addition, they appreciated his adaptability and work ethic.
The Astros are the poster children for the player development movement, but judging from their successes with players like Gonsolin, the Dodgers can’t be too far behind. In an interview with FanGraphs’ David Laurila, Gonsolin said that the Dodgers recommended he replace his sinker with a fourseamer. In 2017, they also had him go through an individualized weighted ball program to improve his velocity. According to Gonsolin, he topped out at 95 mph in college, and he had previously sat 88-92 mph in his professional season. By the end of 2017, his fastball could touch 100.
Though he was optioned back to Oklahoma City on Tuesday, that’s no indictment of his abilities. The Dodgers simply prefer to keep fresh arms on the roster. His debut was marred by some defensive miscues behind him, but he’s been otherwise solid. On Monday night, he pitched six scoreless innings against the Cardinals keeping them hitless through the first five. In his three appearances in the majors thus far, Gonsolin has thrown 14 innings, striking out 13 and walking just one.
His fastball is averaging 94.5 mph while topping out at 96.4 as a big leaguer. Thus far, his fastball hasn’t been as effective at getting whiffs, but there’s room to improve that. One of Gonsolin’s goals is to be effective with it up in the zone. With an average spin rate of 2,451 rpm, Gonsolin gets above average “rise” on the fastball. Fastballs with rise better stay off of a hitter’s swing plane and get more swings and misses especially if they’re thrown higher.
Through his first three outings, Gonsolin has gotten just seven swings and misses on 106 fastballs. It’s an extremely small sample, but Gonsolin has mostly kept his fastballs in the lower half of the strike zone where fastballs are generally less effective.
If his fastball hasn’t met it’s potential yet, we’ve seen what his other pitches can do. The split-finger grades out as his best secondary offering, and it’s what he uses most often. It was his most effective tool for carving up the Cardinals lineup as he got 10 swings and misses on the 23 splits he threw. Gonsolin’s splitter sat 84-88 mph on Monday night. Of the 31 pitchers who have thrown 50 splitters this season, only four have thrown theirs harder than Gonsolin.
The slider has also been an effective swing and miss pitch, as he can throw that at 91 mph. That sort of velocity puts him in company with Jacob deGrom and Zack Wheeler. He’s only thrown a handful of curveballs in the majors, but it has 4.0 more inches of drop according to Baseball Savant.
He was an unlikely candidate out of the draft, but Gonsolin is showing he can be a solid major league pitcher. At the very least, he’s earned a few more looks as the season winds down. With how he pitched Monday, it shouldn’t be long before he’s back in the majors.
Kenny Kelly is a writer for Beyond the Box Score and McCovey Chronicles. You can follow him on Twitter @KennyKellyWords.