"It's a Spring Training type deal, a little soreness in his triceps," Daniels said. "He doesn't feel it at all when he's playing catch. When he ramps up and throws with velocity when he's in a game, that's when he felt it a couple times."
The Rangers were hoping to get Feliz back by the end of August, but that's unlikely with this setback. Feliz has made three appearances during his rehab assignment, two in the Arizona Rookie League and his last with Triple-A Round Rock. He has pitched 2 2/3 scoreless innings with four strikeouts and four walks.
Tepesch could return around early September, as he's now throwing at 120 feet. He was placed on the 15-day disabled list with right elbow inflammation on July 7.
Master Tesfatsion is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.