O'Day has pitched three scoreless innings in his last three outings. He has allowed one hit and one walk while striking out five. Pitching for the second straight day, O'Day struck out the side in order on Saturday. There appears to be little left to prove in the Minor Leagues, and he could be activated during the Rangers' three-game series with the Astros that begins Tuesday in Houston.
"We'll see how [Monday] goes and make a call after that," manager Ron Washington said.
O'Day has been sidelined for two months after undergoing surgery on April 28 to repair a torn labrum in his left hip. O'Day was 0-1 with a 2.45 ERA before having the surgery, and he has a 1.94 ERA in 140 relief appearances over the previous two seasons.
"Yes, we miss him ... he's a big part of our bullpen," Washington said. "The hip has not been a problem. It's just getting into pitching shape, consistently doing what he wants to do with the baseball, and field his position."