Robert Gsellman might’ve been the most frustrating on-field element of the Mets last season. After flashing brilliance in 2016, being ranked as an elite prospect in 2017, and again flashing brilliance in a new role as a reliever at the start of 2018, Gsellman was bad for the majority of the season. The brief periods of success are there, the prospect pedigree is there, and the ‘woah’ moments...
...are there even during his rough stretches. Yet Gsellman posted a 97.8 DRA- (essentially league average), an ERA in the low 4’s, ran an unremarkable K/9, and fell utterly flat when given an opportunity to seize a late inning role.
In a very welcome but somewhat surprising twist, the Mets actually addressed their bullpen this offseason, adding a trio of late inning arms in Edwin Diaz, Jeurys Familia, and Justin Wilson. These additions push Gsellman back into a low-leverage role, which is where he experienced his initial success last year. This also allows the Mets to give Gsellman more of a leash to figure things out - there have been enough signs of talent here to merit giving a 25-year-old more time to improve at the major league level, and it’s easier to allow for that if Gsellman is not serving a late-inning role.
Last July, I took a look at what Gsellman could possibly do to improve going forward, and many of those same conclusions are still valid. Gsellman’s changeup isn’t a good pitch, and if his long term home is the bullpen, it’s not worth using a bad third pitch in games. He could also start throwing his four-seam fastball up in the zone more, which would be a good foil to the sinkers and breaking balls he pounds down in the zone. Perhaps a full offseason of analysis has lead Gsellman or the Mets front office to these or other adjustments he could make to improve going forward. Interestingly, PECOTA expects Gsellman to improve significantly, pegging him for a 3.48 ERA and a DRA around 4 over 60 innings out of the bullpen, which would make him a very nice option in the middle innings.
Even if he doesn’t take a big step forward, there are some creative ways the Mets can try maximize Gsellman’s utility. Deploying him as a multi-inning arm could take advantage of his history as a starter, while also limiting the load on the older or more injury-prone arms in the bullpen. Even more creatively, the Mets could occasionally deploy Gsellman as a Rays-style opener, or piggyback him with Jason Vargas. In this way, two pitchers could create something more than the sum of their parts, as they’d only have to face opposing lineups once and could mess with opposing managers’ lineup preferences due to their opposite handedness.
There are many paths to Robert Gsellman becoming a productive major leaguer, and there’s still plenty of time for him to figure it out. With the roster they’ve constructed for 2019, the Mets have given Gsellman a chance to refine his craft in a low-leverage spot before he gets another crack at a late-inning role down the line. Despite that, the 25-year-old righty can still provide real value for the Mets in 2019, even if it’s not as the big-time closer we all hoped he’d be.