"That's something we've talked a little bit about," manager John Farrell said Thursday. "Any potential role has been put on hold just because of his [injury], but as I've mentioned before, I wouldn't rule out him coming back to us in a shorter role."
In six starts for Boston this season, Kelly has posted an 8.46 ERA. He hit the disabled list in April due to shoulder soreness and faltered in his return, prompting his demotion to Pawtucket on June 1.
Kelly was expected to miss just one start after straining his groin in his first start back with the PawSox, but as of this week, he was still playing catch on flat ground.
"I think the first thing is we've got to get him on a mound," Farrell said. "Hopefully that's going to be Sunday for his first bullpen, with a return to Pawtucket."
After winning eight straight starts last August and September, Kelly has yet to find a rhythm in 2016. He has surrendered 12 earned runs in seven innings over his last two big league starts.
Red Sox president of baseball operations Dave Dombrowski said last month that the club was not considering moving Kelly to the bullpen. But Farrell has said multiple times since Kelly's latest setback that a relief role was not out of the question.
Kelly last pitched out of the 'pen for the Cardinals in 2013 and has a 3.25 ERA in 30 career relief appearances.
"We're looking for reinforcements in depth," Farrell said. "Certainly his power arm, you would think, would be a plus in a shorter stint. Like I said, wouldn't rule it out."
The Red Sox are still searching for a consistent fifth starter. Clay Buchholz, who carries a 5.83 ERA, will keep the spot for now after allowing three runs in five innings on Tuesday in his return to the rotation.
• Catcher Blake Swihart had his left ankle reexamined Wednesday and has transitioned from a walking boot to a brace. Swihart, who was placed on the disabled list June 5, will now begin a regular throwing program. That puts him ahead of schedule, but his return is not imminent. "Encouraging, but still a ways to go," Farrell said.
• Travis Shaw got two at-bats as a pinch-hitter and played three innings in left field Thursday after exiting Wednesday's game due to a right shin contusion. The third baseman was not expected to be available in the field, but his services were needed after left fielder Chris Young strained his right hamstring.
• Catcher Ryan Hanigan (strained neck) will get four at-bats as the designated hitter for Pawtucket on Thursday. Farrell said he would like to see Hanigan play nine innings behind the plate on back-to-back days before his return to the Majors.
• Farrell said infielder Josh Rutledge has "pretty severe" tendinitis in his left knee and has no clear timetable for a return. Rutledge was placed on the disabled list June 17.