Uehara suffered a left hamstring strain just eight pitches after Tatum left Thursday's contest with a left index finger contusion. Both players met with a member of the team's training staff on the field before being escorted off under their own power.
Uehara had a 1-1 count on John McDonald when play was halted for Tatum, who appeared to injure his hand on McDonald's swinging strike. After yielding a double to McDonald, Uehara got ahead of leadoff man Jose Bautista, 0-2, before he, too, headed to the dugout.
"After the last pitch [to Bautista], I felt something in my hamstring," Uehara said through interpretor Jiwon Bang.
The hamstring issue is nothing new to Uehara, who was hampered last season by a left hamstring injury and a partial tear in his right flexor tendon. The Japanese right-hander was shut down for good in mid-September.
On Thursday, Uehara said the injury was in a different spot than last year, but obviously still in the same general area.
"I'm always concerned," Uehara said, when asked if he was worried about the extent of the injury.
Manager Dave Trembley said Uehara will be examined by the team's training staff, with more details expected Friday.
Slated to pitch out of the bullpen this year, Uehara entered Thursday's game with four scoreless spring innings. He had four strikeouts and no walks, picking up his fifth punchout with the first out of Thursday's outing, a swinging strikeout of Travis Snider. Following the injury, Uehara was replaced by Alberto Castillo, who allowed a two-run homer to Aaron Hill, with one of those runs charged to Uehara.
When asked if he was concerned about Uehara, Trembley declined to speculate, saying he would wait to hear the results of the pending evaluation.
Tatum was sent back to Sarasota, Fla., for an X-ray on his finger and was not available for comment. He was replaced by Luis Bernando.
If Tatum's injury is ruled as simply a contusion, it will be welcome news at Orioles camp. The 27-year-old -- who celebrated his birthday Thursday -- is in contention with Chad Moeller for the backup catching job, and the club has already seen Michel Hernandez bow out of the competition with a fractured right index finger.
Tatum entered Thursday 0-for-9 in six games, and he connected for his first hit in the fourth inning, doubling off Blue Jays starter Ricky Romero in his second at-bat.
Brittany Ghiroli is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.