9. Robert Gsellman, RHP
Height: 6'4", Weight: 210 lbs
Acquired: 13th round, 2011 draft
2015: High-A St. Lucie: 51 IP, 37 H, 10 R, 10 ER, 11 BB, 37 K; Double-A Binghamton: 92.1 IP, 89 H, 47 R, 36 ER, 26 BB, 49 K
It was an interesting season for Gsellman, who dominated High-A with a 1.76 ERA but didn't post the lavish strikeout totals we have become accustomed to over the past several years from the Mets' top pitching prospects. He struck out just 37 batters in 51 innings but allowed fewer runs than walks. This performance earned him an early promotion to Double-A, where the lack of swing-and-miss in his repertoire was accentuated; he had just 49 punchouts in about 92 innings. His run suppression was decent there, at least from an earned run perspective, in large part due to a ground ball rate upwards of 50%. In fact, his ground ball rate in High-A was 58%, which is an obscene number of grounders. Both rates are well above average and this goes a long way to explaining the disconnect between his ERA and his strikeout percentage.
Gsellman is such an extreme ground ball pitcher because he has a good, 91-93 mile-per-hour two-seamer that he throws overhand from his 6'4" frame, generating tons of downward plane. He loves to pound the ball down in the zone, too much perhaps, and is quite good at locating the ball around the plate. After the fastball, his favorite—and best—pitch is his curveball, which is a true 12-6 breaker. It's another pitch that produces a lot of ground balls and weak contact. I think my only qualm with the curve is that I wish he threw it more. The changeup is the third pitch, and he threw a few that were very good, but it is definitely a work in progress and not a pitch that really fooled opposing batters. The repertoire is a good one, even despite the lack of swing-and-miss in his results last year. If I had to explain it, I would guess that he became too predictable and not reliant enough on the secondary offerings, particularly the curve. Adding a four-seamer up in the zone to his mix could help change the eye levels on hitters and perhaps add some deception to the two-seamer.
This all adds up to a potential back-end of the rotation starter with a floor of a low-leverage reliever, and I would say that the risk of him reaching that floor is relatively low. Looking ahead, I wouldn't be surprised to see Gsellman start in Binghamton as he works to continue the development of his change and become less reliant on the two-seamer.