3 relief pitchers in DFA limbo that could be the Pirates' next bullpen project

Many of the key pieces in the Pittsburgh Pirates' bullpen were not star players when the Bucs acquired them. Both Justin Lawrence and Dennis Santana were waiver claims, and now figure to be the Pirates' eighth and ninth inning duo. Isaac Mattson was signed out of independent ball. Dauri Moreta had an ERA over 5.00 before the Pirates sent Kevin Newman to the Cincinnati Reds to acquire him. The Pirates are able to find diamonds in the rough at a consistent rate when it comes to their relievers.

Plenty of relievers are entering the 2025-2026 offseason in DFA limbo, and the Pirates should keep an eye out, as one of these three tantalizing arms could soon be up for grabs. They're all hurlers the Pirates should show interest in.

3 possible soon-to-be-DFA'd relievers the Pirates should show interest in

Michael Petersen

Michael Peterson became just the 52nd player from the United Kingdom to play in Major League Baseball when he made his debut in 2024. He is also a pitcher that the Pirates once drafted in the 19th round of the 2012 draft, but did not sign. He was drafted three more times after that, and despite appearing in only two MLB seasons, has already played for the LA Dodgers, Miami Marlins, and Atlanta Braves. He has only tossed 37.2 innings in total, posting a poor 5.02 ERA, 5.09 FIP, and 1.51 WHIP along the way

The right-hander spent the 2025 season appearing in games for the Braves, Marlins, and the LA Angels' Triple-A teams, and his numbers were better than his big league stats. In 36.1 innings, he had a 4.46 ERA (but a 3.87 FIP) and 1.32 WHIP. He got plenty of swings and misses, with an impressive 34.1% whiff rate and 29.2% K%. On top of that, Peterson only walked 7.5% of opponents. His 1.24 HR/9 wasn't good, but his 6.1% barrel rate indicates that the mark may not be sustainable.

Petersen had good Triple-A numbers this year, but that's not why the Pirates should monitor whether or not he gets DFA'd. Simply put, Petersen throws hard, averaging 97.4 MPH with his fastball, putting him above the 90th percentile of fastball velocity. He is primarily a four-seam/cutter relief pitcher, but both pitches grade out well on Stuff+. For his career, Petersen's fastball has a 109 Stuff+, and his cutter comes in at 119. Overall, his Stuff+ comes in at a 112, 

90th+ percentile fastball velocity is not something that is usually found on the waiver wire, let alone a pitcher who throws that hard with a secondary that nearly touches 120 in terms of Stuff+. If Petersen gets designated for assignment this offseason, the Pirates should seriously consider doing what they can to get him in their organization and pitching development program.

Daniel Robert

Daniel Robert was originally a 21st-round pick by the Texas Rangers in the 2019 draft. So far, his MLB career has consisted of 18.2 innings with the Rangers and Philadelphia Phillies over the last two seasons. While he has only allowed six earned runs with 21 Ks in that time, the right-hander has also handed out a dozen free passes, along with surrendering three home runs. 

Robert spent most of his 2025 season for the Phils' and Rangers' Triple-A teams, where he pitched to the tune of a 2.67 ERA, 2.82 FIP, and 1.22 WHIP over 30.1 innings. He struck out his fair share of opponents, with a 27.3% K% and 29.6% whiff rate. Robert was not prone to walks or hard contact either, with a 6.8% BB%, 0.30 HR/9, 86.2 MPH exit velocity, and 4.9% barrel percentage.

When Robert appeared in the major leagues with the Phillies this year, he averaged 96 MPH with his four-seam fastball with average movement. He'll also mix in a cutter, sweeper, and a sinker, which he mainly uses against same-handed batters. Stuff+ likes his pitch mix, grading it out with a career mark of 111. His sweeper, in particular, grades out very well with a career 124 rating.

Robert suffered a forearm strain in September and was placed on the 60-day IL. However, this maneuver may have been used to add another player to the 40-man roster for the final weeks of the season, given that Robert likely would not be returning to the mound in 2025. If Robert is healthy and will be ready to go by the start of 2026, the Pirates should monitor his roster status this offseason. He has already been designated for assignment once in his career; it could very well happen again, and would open up an opportunity for the Pirates to snag a hard-throwing right-hander.

Cam Booser

Cam Booser was one of baseball's best feel-good stories in recent history. A former 2013 undrafted free agent by the Minnesota Twins, Booser stepped away from baseball in 2017 after multiple injuries, including Tommy John surgery, a broken back from a bike accident, and a 50-game drug suspension. Four years later, in 2021, after working in carpentry, Booser re-entered pro ball at the indy level and was signed by the Arizona Diamondbacks prior to the 2022 season. While he didn't make his MLB debut in Arizona, he signed with the Boston Red Sox before the 2023 campaign and made his debut a season later.

Booser put up solid numbers during his rookie season, including a 3.38 ERA, 3.80 FIP, and 1.34 WHIP over 42.2 innings of work. Booser's peripherals all sat around league average. The southpaw owned a  23.4% K%, 8.7% BB%, and 1.05 HR/9, along with an 88.6 MPH exit velocity and 8.1% barrel percentage. Despite the solid start to his MLB career, Booser was traded to the Chicago White Sox last offseason.

However, 2025 was much less promising. Booser only pitched 31 innings, working to a 5.52 ERA, 6.62 FIP, and 1.52 WHIP. While his strikeout rate improved slightly to 24.5%, his walk rate took a massive step in the wrong direction to 13.3%. He was also extremely prone to home runs, with a 2.32 HR/9 ratio. Booser was hit hard by opposing batters, with a 90.9 MPH exit velocity, and a barrel percentage that landed at 13.8%. Booser was even optioned to Triple-A twice during 2025. Nothing is trending in the right direction for Booser ... for now.

The upside from Booser comes from his pure stuff. In 2024, his fastball and cutter resulted in Stuff+ marks of 115 and 106, respectively. In 2025, he had 112 and a 113 Stuff+ grades on both pitches. He also started throwing a changeup that Stuff+ appraised as a 103. His sweeper was the only pitch that got significantly worse, dropping from 114 to just 102 between his time with the Red Sox and the White Sox. Booser's fastball velocity of 95.4 MPH was the 15th fastest of any lefty reliever who threw at least 30 innings in 2025. Having two pitches with a Stuff+ grade over 110 definitely screams "potential," even if Booser is going into his age-34 season.