BOSTON -- Right-hander Edward Mujica is day to day after injuring his oblique while warming up in the bullpen during Saturday's 6-3 win over the A's.
Red Sox manager John Farrell said on Sunday morning Mujica is likely unavailable for the series finale against Oakland.
"This isn't a DL situation as a result of the exam this morning," Farrell said. "He'll continue to receive treatment before we open up with Cincinnati on Tuesday."
Mujica said he threw about 15 fastballs as he warmed up in the bullpen, but felt discomfort on the first changeup he threw.
The Red Sox put the right-hander through a series of function tests on Sunday that focused on his range of motion.
"You have to do this before you put a ball in his hands," Farrell said. "That is the progression he is going through."
After signing a two-year, $9.5 million contract this offseason, Mujica has struggled this season. He's 1-1 with a 9.00 ERA in 11 appearances, allowing 10 runs in 10 innings of work.
Quinn Roberts is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.