While X-rays came back negative, Tatum's injury was serious enough to necessitate a roster move. The catcher was optioned to Triple-A Norfolk.
Tatum suffered the injury when reliever Jason Berken's first pitch to Twins outfielder Jason Repko, a 91-mph fastball, hit off Repko's bat and struck his bare hand, bringing head athletic trainer Richard Bancells out to the mound. Tatum walked off the field with Bancells and was replaced behind the plate by Fox with the Orioles trailing, 5-2.
"I'm just glad I had [my hand] loose and not tight," Tatum said. "I thought it was broken just because it swelled up so fast. I thought it was the knuckle, but that was just the swelling.
"It's just a bruise. The [medical staff] said it wasn't broken and in a couple of days, I should be fine."
Still, the ill-timed injury gave the Orioles an easy decision, particularly considering Tatum has an option remaining while the more-versatile Fox would have to clear waivers to stay in the organization.
Interim manager Juan Samuel said prior to Saturday's game that the Orioles will probably stay with eight relievers and play with a three-man bench given their recent struggles in the starting rotation. He also indicated that team couldn't afford to carry three catchers with the current roster being what it is.
While Tatum has excelled as Wieters' primary backup, the Orioles would almost certainly lose Fox by exposing him to the waiver wire, given that he can play multiple positions and has been effective, hitting three homers and five RBIs in his first 15 games with Baltimore.