Getting to know Mets pitcher Robert Gsellman

The Mets have called up their 2011 13th round pick, Robert Gsellman—our ninth-ranked prospect coming into the season—to replace the DL-bound Steve Matz. Indications are that the Mets plan to use Gsellman out of the bullpen, at least initially, though given the other options on the roster, I wouldn’t be shocked to see him slide into the rotation after a turn or two.

Gsellman was promoted to Triple-A Las Vegas after posting a 2.71 ERA in 11 Binghamton starts. A pulled quad sidelined him for a few weeks after the promotion, and he struggled in the few starts surrounding that injury, but over his last six starts he has posted a 3.72 ERA while striking out 22.3% of batters. Let’s take a look at what the six-foot, four-inch righty has to offer.

The Arsenal

Gsellman’s primary offering is a heavy two-seam fastball that he will throw anywhere from 89-94 miles per hour, but it primarily sits in the 91-93 range. We have had reports of his fastball touching as high as 98 this year, so it will be interesting to see where he can sit out of the bullpen. His curveball has been the favored secondary offering, and it’s a quality pitch that he can throw for strikes or bury in the dirt with two strikes. The changeup is his worst pitch, often sitting firmly up in the zone and lacking break. The fourth pitch—new this year—is the slider, a pitch that has come along quite well given its youth. He throws it primarily to righties, and I’ve seen it feature tight break just off the plate or buried in the dirt for a check swing strike three. The development of the slider has given me renewed confidence that Gsellman could stick in a major league rotation.

What he does well right now

The first thing you notice when watching Gsellman, aside from his flowing locks, is he loves to pound the bottom of the zone with his two-seamer. And with good reason, he hasn’t posted a ground ball rate below 50% in his professional career (major league average this year is ~45%). Likewise, he doesn’t give up a ton of fly balls, which has led to a low home run rate, at least before he got to Vegas. His curveball flashes plus at present, and I’m excited to see what it can do at sea level. Between the curve and the aforementioned slider, Gsellman has at least one solid offspeed offering for either handed batters. And last, but not least, an added bonus: Gsellman works extremely fast. So if he bombs on the mound, at least he’ll be swift about it.

What he doesn’t do well right now

Throw the changeup as anything more than a show-me pitch. It’s definitely the pitch with the most work to be done, although, admittedly, this could be more of an issue with my analysis watching him on MiLB.tv than with the actual quality of the pitch. Though, if we need a secondary source, our old friend Mr. Paternostro agrees. Another issue is that he sometimes won’t turn the curveball over, leaving it up in the zone and on a platter for the hitter. Gsellman can also fall in love with the two-seamer, and if the velocity bumps he’s flashed are real, I would love to see him elevate a four-seamer from time to time.

What to expect

It’s difficult to predict what Gsellman will do out of the bullpen since he hasn’t been in that role before, but given his low-effort delivery and the flashes of premium velocity, I wouldn’t be shocked if we saw him sitting closer to the mid-90s. The slider will be his go-to secondary to righties and the curveball to lefties. He’s not going to strike a lot of guys out, but he will get ground balls and likely post an ERA that is below his FIP. It’s impossible to predict the next few innings of any reliever, so I won’t do that. But for my money, Gsellman is the best fifth (fourth?) starter option currently on the 25-man roster.

In the long-term I’m bullish on Gsellman. Given the Mets’ penchant for developing sliders, it wouldn’t be surprising to see that pitch develop into a plus offering. If he can realize some of the reported velocity gains as well, we could be looking at an average big league starter rather than a sixth starter safety valve or future reliever.