DETROIT -- Kason Gabbard is still feeling discomfort and stiffness in his back and the Rangers are concerned he might not be able to make his next start on Saturday.
Gabbard tried to play catch on Tuesday at Comerica Park and said the problem has not gone away.
"I still feel it when I try to extend my arm and twist my back to throw," said Gabbard, who left his start against the Red Sox on Monday after just two innings.
The Rangers were hoping that Gabbard had nothing more than back spasms that would settle down with treatment, but now they're calling it a strained muscle.
Right-hander Sidney Ponson and left-hander A.J. Murray could be candidates to start if Gabbard isn't ready to go on Saturday. Gabbard is scheduled to have his between-starts bullpen session on Wednesday. If he can't make that session or still has problems throwing, then the Rangers will have to consider somebody else to face the Twins on Saturday.
"We can't make a decision like that until we see how Gabbard is tomorrow," Rangers manager Ron Washington said. "When you're talking about Gabby, I'm always optimistic because he's a gamer. The only thing I don't want him to do is start something he can't finish. I want him to be honest."
Ponson is coming off his best outing for Triple-A Oklahoma on Sunday, pitching seven scoreless innings in a 6-1 victory over Iowa. He is 1-2 with a 3.47 ERA in five games for the RedHawks, including a 1.84 ERA in his last two starts.
The problem is he's not on the 40-man roster. He would have to be added and somebody would have to come off. The other option would be to transfer a player from the 15-day to the 60-day disabled list. Murray, 2-0 with a 5.14 ERA in four starts, is on the 40-man roster and could be brought up without disruption.
Doug Mathis is 4-0 with a 3.12 ERA in four starts at Oklahoma, but he is also not on the Rangers' 40-man roster.
T.R. Sullivan is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.