"If he comes out of tomorrow as he came out of his bullpen [on Friday], we may be looking at just one start," said manager John Farrell.
With Franklin Morales pitching a bullpen session on Sunday and scheduled to pitch four innings for Portland on Wednesday, the Red Sox could have some decisions to make with their rotation. Morales, who is on the 15-day DL with a strained lower back, is being stretched out as a starter.
"Provided all continue through their progression without any setbacks, those decisions are probably in the next week," Farrell said. "Those are good situations to have to decide."
Left-handed reliever Craig Breslow, on the DL with tendinitis in his left shoulder, could also return soon. He'll pitch an inning with Portland on Tuesday.
The Red Sox currently have only one left-handed reliever, Andrew Miller, in their bullpen.
"We always take an approach to take the best pitchers available, regardless of left-handed or right-handed," Farrell said. "Provided Craig gets back to what he's proven over the last few years, and Franklin does as well, that gives us more left-handed options to turn to."
Right-handers Koji Uehara and Junichi Tazawa have both done well against left-handed batters this season. Lefties are hitting just .057 against Uehara and .211 against Tazawa.
"Koji and Taz have been outstanding against them," Farrell said. "But to add some versatility to the 'pen, yeah, that'd be a good thing."
Jason Mastrodonato is a reporter for MLB.com. Follow him on Twitter @jmastrodonato. This story was not subject to the approval of Major League Baseball or its clubs.