(Caption for Photo: Pirates reliever Isaac Mattson pitches to the Dodgers’ Shohei Ohtani on Sept. 2, 2025, at PNC Park. Credit for Photo: (Christopher Horner | TribLive)

Noah Haswell, Beaver County Radio News

(Seattle, WA) Seattle Mariners Executive Vice President & General Manager of Baseball Operations Justin Hollander announced yesterday that the Mariners have claimed right-handed relief pitcher Isaac Mattson off waivers from the Pittsburgh Pirates.

The thirty-one-year-old Mattson appeared in 38 games with the Pirates in 2026 and posted a 5.35 ERA (23 earned runs, 38.2 innings pitched), along with 18 walks, 36 strikeouts and a 1.60 WHIP.