The Athletics selected Serven's contract from Triple-A Las Vegas on Saturday.
Shea Langeliers is currently working through a thumb injury, so the Athletics will bolster their depth at catcher by calling up Severn while Jonah Heim serves as the No. 2 option. Severn has spent the entire 2026 season in Triple-A, where he's slashing .295/.392/.505 with seven home runs and 40 RBI in 227 plate appearances. He last saw major-league action in 2024 with the Blue Jays, when he appeared in 28 regular-season games while posting a .465 OPS over 71 plate appearances.