The Diamondbacks recalled Jameson from Triple-A Reno on Saturday.
The move corresponds with Kade Strowd being optioned to Reno following Friday's game against the Nationals. Jameson has spent the entire 2026 season in Triple-A, where he has a 7.33 ERA, 1.60 WHIP and 23:12 K:BB across 23.1 innings. He appeared in three regular-season games for the Diamondbacks in 2025, allowing two runs (one earned) on four hits and three walks over three innings while logging one save.