The Reds signed Ferguson to a one-year contract Tuesday, Gordon Wittenmyer of The Cincinnati Enquirer reports.
Ferguson made 70 regular-season appearances in 2025 between the Pirates and Mariners, posting a 3.58 ERA and 51:22 K:BB over 65.1 innings. The southpaw held left-handed hitters to a .184/.261/.204 batting line, so Ferguson should be leaned on heavily by manager Terry Francona in 2026 when the opposition has lefties due up.