Since shifting right-hander Robert Gsellman into a relief role at the start of the 2018 season, the 25-year-old has shown flashes of brilliance but has also battled bouts of inconsistency for the New York Mets. This team needs him to start exhibiting more of the former and less of the latter.
Over 68 appearances as a reliever last season, Gsellman owned a 4.28 earned-run average with a 3.95 fielding independent pitching rating, 1.30 WHIP, and 2.50 strikeouts-to-walks. Respectable enough for a newly-converted relief arm.
He was outstanding over the first month of the season (1.80 ERA with 11.4 strikeouts per nine over 13 appearances), pitched to a 5.11 ERA over 44 innings pitched from May 1 to the end of July, performed beautifully in August (1.54 ERA with a .167/.186/.286 slash line against over 11 appearances; 11.2 innings), then allowed eight earned runs over 9.1 September innings.
When he was on, Robert Gsellman was fantastic. But when he fell, he fell hard. Heading into 2019, the Mets were counting on Gsellman to shoulder a heavy load coming out of the bullpen and were surely hoping to find their young righty on more of an even keel.
After allowing three runs over his first four outings (four innings), the Los Angeles native appeared to shake off the rust and rattled off a string of seven appearances that compared favorably to his shining runs of success last season.
Over 10 innings from April 7 to April 21, Gsellman pitched to a 0.90 ERA with 10 strikeouts, two walks, and a .162/.205/.351 slash line against. Before his hot stretch come to a screeching halt in the eighth inning on Wednesday versus the Phillies, Robert Gsellman was looking downright dominant.
He’s been using his slider 32.7% of the time — a considerable increase from his 16.6% slider usage in 2018 — with terrific results. Not only is he throwing his slider faster than any other reliever in the major leagues (91.5 mph), he’s found success with it as his out-pitch.
Gsellman’s got a .091/.273/.182 slash against and five strikeouts via his slider with two strikes (11 at-bats). Since he moved into the Mets’ bullpen in 2018, MLB hitters are slashing just .169/.262/.092 against his slide piece. That’s a bonafide weapon, folks.
A curious aspect of Gsellman’s arsenal has been the neglect of his curveball. He’s got a .158/.211/.053 slash line against versus his deuce since 2018, but has used it sparingly — at best. After mixing it in 11.9% of the time last season, the 25-year-old’s only thrown 19 curves this season.
Though, I’m seriously at a loss as to why exactly. Gsellman’s curveball hasn’t resulted in a base hit yet this season. The 2,836 average rotations per minute he gets on it ranks 21st in MLB among all qualified hurlers. Again, this looks to be an underutilized but incredibly effective weapon at Bob Gsellman’s disposal.
Hopefully, Gsellman got most of his hard times out of the way early this season and after Wednesday night’s three-earned-run, five-hit debacle, he can find his way back into the groove he had settled into so nicely.
Among qualified MLB relievers this season, Gsellman’s 1.20 walks per nine innings is good for 21st in baseball. That’s a plus. His 4.20 ERA is a bit high, but as long as he can keep finding his way back into those wonderful grooves and limiting the time he spends on the ropes, he should be just fine.
Whether he’s simply finding a feel for his pitches, as well as his approach, or just hitting natural developmental speedbumps along the way, Robert Gsellman clearly has a ton to offer the Mets. At his best, he could be an absolute force.
