"He'll be reexamined here when he comes in [Sunday]," said Red Sox manager John Farrell. "Potential for a DL."
Morales pitched 2 1/3 innings, giving up five hits and four runs. He came out with two outs in the seventh.
The disabled list is where Morales was when last season ended, and when this season started.
"On one pitch, I felt a little something," said Morales.
Morales didn't start his 2013 season until May 30. Saturday was his sixth appearance of the season.
"That's crazy, man. But, I stay positive," said Morales.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.