Rangers right-handed pitcher Alexi Ogando is likely to miss 4-6 weeks with a strained right groin.
Ogando, 28, joined Derek Holland and Pedro Feliz on the disabled list Monday after an MRI showed a muscle tear in his right groin.
Ogando was making his first start of the season after pitching out of the bullpen and felt pain in his right groin beating out a bunt single in the fourth inning against the San Francisco Giants.
Ogando joined the rotation because of injuries to Holland (shouler) and Feliz (elbow). He was an All-Star as a starter last season but shifted back to the bullpen because Feliz, who had been the Rangers' closer, joined the rotation along with Japanese right-hander Yu Darvish.
The Rangers are awaiting the arrival of newly signed right-hander Roy Oswalt. He's scheduled to start Tuesday in Double-A Frisco, his third minor-league start.