5 under-the-radar free agent relievers the Pirates should pursue

The Pittsburgh Pirates’ bullpen was a huge letdown in 2024. Their relief corps originally looked like it could be one of the most formidable late-inning groups in the game. However, a myriad of injuries, as well as underperformance from arms that were slotted into important, high-leverage roles, ended up being one of the biggest reasons for the Pirates’ collapse during the second half of the season.

The Bucs need to prioritize improving their bullpen this offseason, as while there are some talented arms, the group still needs work. Luckily, they have a lot of options on the free agent market this fall and winter, including a handful of more under-the-radar free agents the team should definitely keep in mind.

5 under-the-radar bullpen free agents the Pirates should chase this offseason

Mike Soroka

Mike Soroka finished second place in Rookie of the Year voting in 2019 with the Atlanta Braves. At the time, Soroka looked like a long-term rotation anchor for them, but he unfortunately suffered multiple Achilles injuries from 2020 through 2023, pitching just 46 frames in 10 games (nine starts) for Atlanta before being shipped off to the Chicago White Sox last offseason.

The numbers for the right-hander weren’t pretty, as Soroka put up a 4.74 ERA, 4.95 FIP, and 1.38 WHIP in 79.2 innings. He had a respectable 24.2% strikeout rate, but was prone to both home runs (1.47 HR/9) and free passes (12.7%). Both were a far cry from Soroka’s rookie season, in which he walked 5.8% of batters with a league-leading 0.72 HR/9 in his rookie year, 

So why should the Pirates even consider adding a pitcher with an ERA and FIP approaching 5.00? Soroka was eventually moved to the bullpen, and pitched 50 innings with a 2.75 ERA and FIP, along with a 1.22 WHIP. Soroka’s 9.7% barrel rate was below average, but his exit velocity was an elite 85.3 MPH. The former Rookie of the Year finalist struck out batters at an outstanding 39% rate. The only pitcher who threw at least 30 frames as a reliever with a better K% was Mason Miller. He struggled to limit walks and had a 13% BB%, but on the plus side, he saw his HR/9 plummet from 2.1 as a starter to 0.8 as a reliever.

Soroka also saw a huge step forward in overall ability when he pitched out of the bullpen. Stuff+, a stat on a similar scale to wRC+ or ERA+ that shows the quality of a pitcher’s offerings based on velocity, movement, spin, and arm angle, had Soroka had a paltry 91 when working out of the White Sox’s rotation. But when he was moved to their bullpen, he saw that skyrocket to 102.

MLB Trade Rumors estimates Soroka will earn a two-year deal at $14 million ($7 million AAV). Soroka is still young, as he is only in his age-27 season next year. He may not end up being the ace starter he looked like early in his career, but the way he pitched out of the bullpen was very promising. 

Paul Sewald

Paul Sewald entered the season as the Arizona Diamondbacks’ closing pitcher. After three straight strong seasons with the D-Backs and Seattle Mariners, expectations were high for Sewald. But he fell short of those, as he worked to a 4.31 ERA, 3.95 FIP, and 1.13 WHIP across an injury-limited 39.2 innings of work.

Sewald still struck out batters at a solid 26.1% rate, but more importantly, he put up a career-best 6.1% walk rate. Sewald was prone to hard contact with a 90 MPH opponents' exit velocity, paired with a 9.2% barrel rate. While the 2024 season did not go as planned, there is reason to believe Sewald could rebound in 2025.

For starters, Sewald has a very good track record. From 2021 through 2023, Sewald owned a 2.95 ERA, 3.51 FIP, and 0.98 WHIP. The right-hander was also durable during those three seasons, tossing at least 60 frames in each campaign. He punched out 33.9% of opponents along the way with a respectable 8.6% walk rate. Despite an 86.8 MPH exit velocity, Sewald was always prone to home runs with a 1.33 HR/9 and 9.1% barrel rate across 2021-2023.

Another reason Sewald could rebound is because his stuff was still decent. Stuff+ still held him in high regard at 118. That’s a step down from 127 from 2021-2023, but it was still the best among any Arizona Diamondbacks pitcher with at least 30 frames. A third reason why Sewald could rebound is because ERA estimators liked his work. xFIP did not, as it put him at 4.31, but SIERA (3.48) and xERA (3.78) were much kinder to his body of work.

Jose Leclerc

Jose Leclerc has been a stalwart in the Texas Rangers’ bullpen for years now, finding his groove during their 2023 World Series run. While the hard-throwing righty is coming off a season with an ERA approaching the mid-4.00s, his previous track record, along with some of his other peripherals, suggests he could return to form in the near future.

Leclerc pitched 66.2 innings this year, working to a 4.32 ERA, but a far superior 3.48 FIP and 1.32 WHIP. The right-hander has always carried a high punchout rate, and 2024 was no different, with a 30.9% K%. He has also typically been good at silencing home runs, and put up an 0.95 HR/9 rate with an above-average 87.4 MPH exit velocity (84th percentile) and 7.4% barrel rate (56th percentile). But free passes have always bothered Leclerc, and he had an 11.1% walk rate during this off year

There’s never been a question about Leclerc’s stuff. Stuff+ pinned him at 110. He was in the 70th percentile of fastball velocity with above-average vertical movement on the pitch. ERA estimator numbers also pinned Leclerc as a solid arm. His 3.26 SIERA and 3.48 xFIP were both the best he’s put up since 2018.

Leclerc has been a solid reliever for years now, and 2024 was the first time he’s put up a below-average ERA+, but nothing much changed between his peripherals year-over-year. Plus, most of his struggles can be traced back to the first month and a half of the season. Leclerc has experience closing games out, including as recently as 2023 when he recorded four saves in the Rangers’ aforementioned World Series run.

Tommy Kahnle

Tommy Kahnle is coming off yet another quality season with the New York Yankees. The right-hander has served as a set-up man the past two seasons for the Bronx Bombers, and is a hurler the Pirates could very much use in their bullpen for the 2025 campaign.

Kahnle pitched 40.2 innings, working to a 2.11 ERA, 4.01 FIP, and 1.15 WHIP. Kahnle struck out 25.7% of his opponents. That’s still solid, but a departure from the 29.4% K% he had in 2022-2023. Kahnle had a 10.6% BB% last year, relying almost entirely on his wicked changeup. Kahnle has always been great at limiting quality contact, and 2024 featured more of the same. He held opponents to just an 86.2 MPH exit velocity with a barrel rate of just 6.3%. Despite that, he had a pedestrian 1.06 HR/9 rate.

That indicates Kahnle could definitely benefit from a more pitcher-friendly environment. Yankee Stadium is more favorable to hitters, especially for lefties, compared to PNC Park. Kahnle had some drastic home/away splits. When at home, Kahnle owned a 3.38 ERA, 4.50 FIP, and 1.29 WHIP, while opponents had a .311 wOBA against him. But as a guest, Kahnle had an 0.48 ERA, 3.38 FIP, 0.96 WHIP, and opponents managed a .233 wOBA against the veteran righty reliever. Kahnle was also better on the road in 2023 while with the New York Yankees. 

Kahnle is older, as 2025 will be his age-35 season, but his abilities are still as good as ever. Stuff+ put his pitch quality at a 111 rating. He should also benefit from a move outside of a stadium that heavily favors left-handed hitters to one that is much less kind to lefties.