"I'm disappointed, but at least the doctor says it is nothing severe," said Scheppers, who is transitioning from a late-inning bullpen role to that of a starter.
Rangers manager Ron Washington said Nick Martinez is the most likely candidate to move into Scheppers' place in the rotation Tuesday at Oakland. Scheppers, the Rangers' Opening Day starter, has been plagued by the big inning. In four starts, he is 0-1 with a 9.82 ERA.
To fill Scheppers' roster spot, the Rangers purchased the contract of 27-year-old left-hander Aaron Poreda from Round Rock. Poreda was a first-round draft choice of the White Sox in 2007.
"The wake-up call today was one of the best I've ever gotten," the 6-foot-6, 240-pound Poreda said. "The biggest thing I needed to do when I didn't make the team coming out of spring was work on my durability. Coming off Tommy John surgery, I had to get ready to pitch on back-to-back days. I think I'm ready."