The Pittsburgh Pirates have multiple options to round out their rotation. Carmen Mlodzinski is throwing his hat back into the ring for another go as a starting pitcher. Top prospect Hunter Barco will be in the running. So will offseason signee José Urquidy. However, it doesn’t seem like many fans are taking Thomas Harrington’s bid for the rotation as seriously as the rest. While he is coming off a down year, don’t sleep on the right-hander, not just making the rotation out of Spring Training, but making a sizable impact in 2026.

An Unimpressive 2025 Lowered His Prospect Stock

2025 definitely didn’t go the way Harrington likely hoped it would. He owned a 5.34 ERA, 5.55 FIP, and 1.31 WHIP over 96 innings at Triple-A Indianapolis. His 21.7% strikeout rate was slightly worse than league average, and his 8% walk rate was better than average. Harrington struggled the most with keeping the ball in the yard. His HR/9 ratio clocked in at 1.88. His 90.5 MPH exit velocity and 8% barrel rate were both worse than the Triple-A average.

Harrington briefly pitched in the Majors in 2025, but performed rather poorly. It was a small sample size of just 8.2 innings where he allowed 15 earned runs. The right-hander walked as many batters as he struck out, allowing seven of each. Home runs continued to give him problems in the Majors, as he surrendered three more. His first impression was not very good, to say the least.

Don’t Forget How Good He Pitched Before 2025

Sure, 2025 was an uneventful season for Harrington. However, he established himself as a top prospect after a breakout 2024 campaign. He worked to the tune of a 2.61 ERA, a 3.11 FIP, and just a 0.96 WHIP over 117.1 innings between Altoona and Indy. Harrington got strikeouts at a 25.1% clip and walked just 4.1% of opponents. His BB% was the fourth-best of any minor league pitcher who tallied 20+ starts. He was also one of only 34 minor league hurlers with a K-BB% over 20% in 20+ starts. At 21%, Harrington ranked 24th in this regard. The right-hander also pitched well in 2023, where he had a 3.53 ERA, 27.8 K%, and 7.8 BB% between Bradenton and Greensboro.

Harrington has never lit up a radar gun with impressive velocity. He sat at 92 MPH in the Major Leagues last season. But he did it with 10.7 inches of arm-side break. Although he had slightly below-average vertical movement at 17.2 inches, he was well above average in horizontal movement. His mid-80s cutter also has above-average movement. His splitter got plenty of whiffs, both in the Majors (40% whiff rate) and Triple-A (33.7%). Harrington’s sweeper also induced a whiff at a solid 33.3% rate in the Majors and 32.4% in Indy. His best ability is his ability to locate. That shouldn’t be a surprise, given his sub-5% BB% in 2024.

Aug 1, 2025; Denver, Colorado, USA; Pittsburgh Pirates relief pitcher Thomas Harrington (78) delivers a pitch in the fifth inning against the Colorado Rockies at Coors Field. Mandatory Credit: Ron Chenoy-Imagn Images

Harrington arguably has the highest ceiling among any other player in the running for the final rotation spot. He ranked as high as Baseball America’s 74th best prospect going into 2025. Overall, Harrington was a consensus top 100 prospect at this time last year. Barco is a top 100 prospect by MLB Pipeline, but not by Baseball America. Harrington’s 2024 campaign was also better than Barco’s 2025 season. Urquidy has always been seen as a back-of-the-rotation-type arm, even during his best seasons with the Houston Astros. Now, he is coming off multiple injury-riddled seasons. Mlodzinski has struggled to get through the order a second time in the past.

Harrington needs to earn the rotation spot, just like Barco, Mlodzinski, and Urquidy. But don’t count him out even after an unimpressive 2025. He is only 24 and doesn’t turn 25 until July. The Pirates have done well with their pitching development. He didn’t become a top prospect overnight and for no reason. Harrington still has the potential to be a part of the Pirates’ rotation in the long run.

 

Main Photo Credit: Jonathan Dyer-Imagn Images