Pittsburgh Pirates: Robert Stephenson Could Provide Bullpen With a Boost

The Pittsburgh Pirates recently activated Robert Stephenson from the injured list, and he could provide the bullpen with a needed boost

Going into the season, the Pittsburgh Pirates bullpen was an area of potential major weakness. Although the team's bullpen has looked pretty decent early in the year, they have received another piece of depth that could help them out this season. That’s right-hander Robert Stephenson, who was recently activated from the injured list.

The back of Stephenson’s baseball card may look more like a DFA candidate than a major bullpen reinforcement. Before the Pirates acquired the reliever late last season, he had a 6.04 ERA, 4.66 FIP, and 1.48 WHIP with the Colorado Rockies. While his 6.6% walk rate was strong, he struck out less than 20% of the batters that squared off against him (18.1%), and allowed home runs at a 1.61 HR/9pace. Although Stephenson has been good in the past, he has a career ERA approaching 5.00 at 4.90, and FIP also approaching 5.00 at 4.82.

However, Stephenson pitched well since being acquired by the Pittsburgh Pirates. It was only 13.1 innings, but he struck out 18 batters while just one batter reached base via free pass. Home runs were still a tad high as he allowed two home runs, but he only allowed five earned runs. All told, he had a 3.38 ERA, 2.81 FIP, and 0.83 WHIP.

Those numbers are in a small sample size of fewer than 15 innings. The bottom line stats aren’t going to be much use, so more pitch metric data will be more useful to us here. Where Stephenson struggled was with the use of his fastball. Stephenson’s fastball was downright bad in 2022, as opponents had a .386 batting average, .658 slugging percentage, and .459 wOBA against it. His slider, however, was outstanding and one of the better of its kind in the league. Stephenson held opponents to a .170 average, .357 slugging, and .264 wOBA when he used his primary breaking pitch.

Batters swung and missed at the pitch 44.4% of the time, which was higher than Gerrit Cole, Dylan Cease, or Emmanuel Clase. His slider also induced a better wOBA than National League Cy Young winner Sandy Alcantara with his slider and wasn’t far off from LA Dodgers’ ace Clayton Kershaw at .260.

Stephenson used his slider nearly 70% of the time after arriving in Pittsburgh, compared to just 45% with Colorado. While his slider usage skyrocketed, his fastball usage plummeted from 53.6% to just 28.2%. Stephenson recently made his 2023 debut after starting the first two weeks on the IL. In his return, he faced Tyler O’Neill and Dylan Carlson. He got O’Neill to fly out weakly to center field and struck out Carlson on eight pitches. Of those eight offerings, only one wasn’t a slider, that being an 87.5 MPH cutter. Given that his one cutter was over three MPH faster than his fastest thrown slider, this could be a new pitch he is working on.

It’s pretty evident Stephenson can be really good when he uses his slider. He’s also shown some ability to be decent in high leverage. In 2019 and 2021, his best seasons, he held opponents to an OBP under .300 and BA under .200 in late and close games. It would be nice if Stephenson can turn himself into another late-inning set-up option for the Pirates.

David Bednar, Colin Holderman, Jose Hernandez, Dauri Moreta, and Wil Crowe have been a solid quintuple to start the season. However, it’s fairly bleak past that. Duane Underwood Jr. holds close games like a strainer holds water, as has Chase De Jong (although he is currently shelved on the 15-day IL). Stephenson has shown talent in the past, and hopefully, can be a key member of the bullpen this season after making some major adjustments.