The Pirates announced today that they have selected the contract of right-hander Isaac Mattson. He’ll take the active roster spot of fellow righty Colin Holderman, who lands on the 15-day injured list due to right thumb inflammation. To open a 40-man spot for Mattson, infielder Nick Gonzales was transferred to the 60-day injured list. Noah Hiles of the Pittsburgh Post-Gazette relayed the Mattson and Holderman moves prior to the official announcement (link one, two and three).
It’s been an unfortunate season for Holderman so far, who already spent time on the IL due to a right knee sprain in April. He has allowed 15 earned runs in 15 innings, giving him a flat 9.00 earned run average. He has 11 strikeouts and walks apiece, giving him a 14.9% clip in both of those categories, both of those being worse than average.
Perhaps the injuries provide an explanation for his struggles, as he was far better in previous seasons. Over the 2023 and 2024 campaigns, he had a 3.52 ERA in 107 1/3 innings, pairing a 24.6% strikeout rate with a 9.7% walk rate.
Ideally, a bit of a rest period will get him healthy and back on track. It’s turning into a lost season for the Bucs, as their 15-33 record has them near the National League basement, with only the Rockies beneath them. Holderman is under club control through 2028, so it would make sense to prioritize his long-term health as opposed to benefitting the team in the short term.
Taking his place is Mattson, who is having a strong 2025 so far. The 29-year-old signed a minor league deal with the Bucs in December and has been with Triple-A Indianapolis all year so far. He has logged 18 innings for that club with a 2.50 ERA, 30.6% strikeout rate and 6.9% walk rate.
Those are encouraging numbers, though in a small sample. From 2021 to 2024, Mattson tossed 156 1/3 innings on the farm with a 3.91 ERA and 28.2% strikeout rate but a 13.7% walk rate. So far this year, he has basically cut that walk rate in half. If he can keep that up, perhaps he’ll get some runway to add to his major league track record, which currently consists of a 5.59 ERA in 9 2/3 innings. However, he does have options, so it’s possible the Bucs shuttle him back to Indianapolis when they need a fresh arm.
As for Gonzales, he landed on the 10-day injured list on March 28th due to a non-displaced fracture in his left ankle. His 60-day count is retroactive to that initial IL placement, so he’ll be eligible to be reinstated about a week from today. He started a rehab assignment on Saturday but it seems the Bucs will let him get a few more minor league contests under his belt, which is understandable since he’s been out of action for close to two months.
Photo courtesy of Charles LeClaire, Imagn Images
