Caleb Thielbar
Caleb Thielbar had three straight seasons from 2021 through 2023 with an ERA under 3.50 while striking out over 30% of his opponents with a 30.6% K%. Thielbar also only walked batters 7.3% of the time, keeping control nicely. Unfortunately, his 2024 season did not look nearly as good on paper.
Thielbar pitched 47.1 innings, working to a 5.32 ERA, 4.10 FIP, and 1.56 WHIP in his age-37 season. The southpaw saw his K% plummet to 24.5%, while his walk rate rose to 11.1%. Thielbar's 1.14 HR/9 was about average for him, as he'd posted a 1.17 HR/9 throughout his three previous seasons.
Despite Thielbar's advancing age, his stuff looked as good as ever. His 93.2 MPH four-seam velocity represented the highest average of his MLB career. Both his sweeper and curveball saw an uptick in velocity. Stuff+ pinned him at 111, which was the best of his career as well. His 105 Location+ indicated that he was executing his pitches.
Expected numbers were kinder to Thielbar's work. He had a sub-4.00 SIERA at 3.95, along with a 4.21 xFIP. His main issue was his batting average on balls in play. Over the previous three seasons, Thielbar averaged a 3.33 ERA with a standard .294 BABIP. This past season, Thielbar had a .331 BABIP.
Thielbar also posted an 87.1 MPH exit velo and 10% barrel rate the previous three seasons, compared to 88.2 MPH with a 10.1% barrel rate this year.
Despite approaching 40, Thielbar still has the stuff and some decent numbers under the hood. A low-cost deal to add a lefty to a bullpen that needs it badly could work out very well for the Pirates. Thielbar is another lefty with a lot of potential to rebound in 2025.