Isaac Mattson Claimed Off Waivers by Seattle Mariners From Pirates

The Seattle Mariners claimed 31-year-old right-handed reliever Isaac Mattson off waivers from the Pittsburgh Pirates. Mattson features an extreme fly-ball profile driven by a high-spin 93-96 mph four-seam fastball that he throws over 70% of the time, complemented by a slider and changeup. After a strong minor league campaign in 2024, the reliever established himself in Pittsburgh's bullpen during the 2025 season.