The Mariners non-tendered Santos (knee) on Friday, Francys Romero of BeisbolFR.com reports.
Santos made just eight appearances for Seattle and six appearances on a rehab assignment in 2025 due to right knee surgery. He was pitching by the end of the season, so the reliever should be healthy heading into spring training, but the Mariners opted against tending him a contract. Santos appeared in only 16 games in two years in Seattle due to injuries.