This year has been one of transition and adjustment for right-handed pitcher Robert Gsellman. After being used nearly exclusively as a starter between 2016 and 2017 (29 of his 33 appearances were starts), he hasn’t moved out of the bullpen for the entirety of 2018 (56 appearances and 69.2 innings).
When looking at his performance from a season-long perspective, Gsellman has taken quite well to this change in role. Simply looking at his 3.62 ERA and 3.88 SIERA thus far wouldn’t tell the whole story on how exactly he’s handled the ups and downs that sometimes come with being a reliever, though.
If we take a look at his month-by-month production in a number of areas, it’d be easy to see that it’s been, well, a little bit of a roller coaster. The important part is that the 25-year-old righty is currently on the upswing as we round the final turn over the regular season.
The Basics
While the Mets actually looked like contenders in April, Gsellman was one of the bright spots out of manager Mickey Callaway’s bullpen. The young righty posted a sparkling 1.80 ERA through his first 15 innings of work to go along with a .251 wOBA allowed, 30.2% strikeout rate, and 9.5% walk rate.
The roller coaster — at least with regard to his ERA and walk rate — began once the calendar flipped to May.
| Month | IP | ERA | wOBA allowed | K% | BB% |
|---|---|---|---|---|---|
| April | 15.0 | 1.80 | .251 | 30.2% | 9.5% |
| May | 19.2 | 4.58 | .319 | 14.5% | 10.8% |
| June | 13.2 | 6.59 | .306 | 25.4% | 7.9% |
| July | 10.2 | 4.22 | .333 | 14.9% | 10.6% |
| August | 10.2 | 0.00 | .114 | 18.9% | 2.7% |
We’re obviously talking about much smaller sample sizes because of his role, but it’s pretty clear to see that he struggled mightily, hit a wall, or whatever you’d like to call it, between May and June prior to getting himself back on track in July and kicking it up another notch in August.
Watching that strikeout rate creep back toward 20.0% like it had in April and June would be more ideal, but it’s not so bad when Gsellman’s walk rate is under 10.0% — especially as an important late-inning reliever that’s been getting a handful of save opportunities these days.
Stranding Runners
Since it’s seemed as though Gsellman and Seth Lugo were the only two dependable relievers the Mets had during significant chunks of this season, they’ve both found themselves in high leverage situations rather frequently.
And at certain points in the year — mostly in that May and June range — it felt like Gsellman was giving up at least one run every time he took the mound. When looking at the month-by-month progression in his BABIP allowed and strand rate (LOB%), none of that would be surprising to see or hear.
Just as a point of reference, the league-average BABIP for relief pitchers in 2018 is .298, while that number is 73.4% for strand rate.
| Month | IP | BABIP | LOB% |
|---|---|---|---|
| April | 15.0 | .342 | 79.0% |
| May | 19.2 | .259 | 75.6% |
| June | 13.2 | .290 | 46.5% |
| July | 10.2 | .250 | 68.2% |
| August | 10.2 | .138 | 100.0% |
Talk about going from the sublime (June) to the ridiculous (August). His current dominant stretch as we head toward September has certainly helped Gsellman’s overall stats look better, but it’s not as if things have been mostly smooth sailing. He’s definitely had to figure some things out along the way.
Quality of Contact
Guess what? Gsellman’s batted-ball profile and quality-of-contact numbers are mirroring this same roller coaster ride we’ve been mentioning regularly. Here’s a month-by-month look at how his line-drive rate (LD%), ground-ball rate (GB%), fly-ball rate (FB%), and hard-hit rate (Hard%) compare to one another this season.
| Month | LD% | GB% | FB% | Hard% |
|---|---|---|---|---|
| April | 18.9% | 59.5% | 21.6% | 29.0% |
| May | 20.3% | 54.2% | 25.4% | 31.2% |
| June | 15.4% | 38.5% | 46.2% | 45.0% |
| July | 12.1% | 54.5% | 33.3% | 29.4% |
| August | 10.3% | 58.6% | 31.0% | 17.2% |
Once again, we see this trend — specifically when looking at his ground-ball rate, fly-ball rate, and hard-hit rate allowed — where things started great before progressively getting worse the following couple months before improving.
The dominant numbers he’s produced in August shouldn’t be a surprise because virtually all of the peripheral statistics outlined here during this current month are the ones that resemble April the most.
Finding a Home?
Overall, this adjustment has been a success for Gsellman, who ranks among the league leaders in relief innings pitched so far this season, along with Lugo. Without a lot of flexibility in the rotation and a mostly unsettled bullpen heading into the offseason, they both could very well be in similar roles once 2019 rolls around.
Lugo still has a desire to start, but it sure seems as if Gsellman has fully taken on this relief challenge with open arms.
The bullpen needs a complete overall this winter if New York plans on contending next year, but we’re all aware of both the Mets’ imaginary limitations and the crapshoot it can be to acquire relievers (See: Swarzak, Anthony). So with all that in mind, it’s likely that Gsellman will not only be in the bullpen, but also have a vital role when it comes to locking down the late innings.
