By any reasonable metric, Dillon Overton’s major league debut last season was an unmitigated disaster. He was called up in late June and made five forgettable starts for the Athletics. In those 21 innings, he allowed 43 hits, 26 runs, and 11 home runs—good enough for a 10.97 ERA and a 9.52 FIP. So despite these early career struggles, it was surprising to me when the Mariners were able to acquire the former second-round draft pick in exchange for a ninth-round, defense-first catcher.
As recently as the 2015-16 offseason, Overton was ranked as high as eighth in the A’s organization. So how did he lose that prospect sheen so quickly? His major league debut was certainly part of it but there’s more to it. He was drafted by the A’s in 2013 but required Tommy John surgery immediately after signing. In college, he could hit 94-95 mph with his fastball but that velocity never returned. Without the velocity to fall back on, Overton now has to rely on his command and his secondary pitches to succeed.
Fortunately, he possesses a solid foundation to build upon: an outstanding changeup. Among all starting pitchers who threw a changeup last year, Overton’s generated the 22nd highest whiff rate. He throws the pitch around 79-80 mph—a 10 mph difference from his fastball—with excellent horizontal movement. Let’s see it in action:
It’s not the best camera angle but we can see why Springer was so badly fooled on this changeup. Overton buries this changeup down and away, using the pitch’s natural movement to hit his spot. Springer is way out in front and the pitch is moving away from him—he has absolutely no chance to hit this pitch.
With such a good changeup, Overton is well suited to negate a right-handed batter’s platoon advantage. I don’t have detailed minor league splits available to me, but last year, across all levels, he was able to generate a higher strikeout rate against righties than lefties (19% vs. RHB, 17% vs. LHB).
The rest of Overton’s pitch repertoire is a work in progress. His curveball is merely average but he did add a cutter last season that showed some promise. The amount of horizontal movement he’s able to generate with that pitch is impressive, the fifth highest amount of break among lefty starters who threw a cutter. On the surface, the pitch doesn’t seem to be all too effective from a results standpoint. But isolating its results against right-handed batters and we see its promise. He was able to generate an above average amount of whiffs with the cutter against righties and when he wasn’t making them miss, they were fouling it off 35% of the time. Let’s pick on George Springer one more time:
Overton hits his spot perfectly and Springer is badly fooled again. We’re only working with a sample of 31 cutters so it’s hard to draw any conclusions about the pitch yet. It certainly shows promise as a weapon against right-handed batters, giving Overton another tool to neutralize his platoon split.
In both of the examples above, Overton showed off his other tool: his command. Across three minor league seasons, Overton’s walk rate was an excellent 5.2% and he was able to maintain that rate when he made the jump to the majors. But while he wasn’t walking anyone, batters were teeing off on the fastballs he threw in the zone.
Without his fastball velocity, he’s a soft tossing lefty with good command and an excellent changeup. There’s some promise there, especially if he can find that missing velocity or continue to develop his cutter. He’s the perfect project for the Mariners player development staff. For now, he’ll be another piece of depth for a team flush with young, projectable pitchers.