"At this point moving forward it's probably not going to be the best thing to run him back out there," said interim manager Torey Lovullo. "We just want to make sure we get the photos, get the imaging and want to make sure we know what's going on there. Much like [Junichi Tazawa], we want to set this up for 2016 and make sure guys are healthy and ready for the regular season."
Kelly struggled mightily earlier in the season and was optioned to Triple-A Pawtucket in June. He went 8-0 with a 2.59 ERA in an eight-start stretch between Aug. 1 and Sept. 9.
Kelly finished his first full season in Boston with a 10-6 record and a 4.82 ERA.
With Steven Wright (concussion), Clay Buchholz (right elbow) unavailable and the Red Sox trying to keep young pitchers Henry Owens and Eduardo Rodriguez at certain innings thresholds, Lovullo will do the best he can to piece together the rotation for the rest of the season.
Rick Porcello, Wade Miley, Rodriguez, Owens and Rich Hill are the current starters in the rotation.
The six-man rotation the Red Sox had been using over the last week won't be able to work anymore because Lovullo simply doesn't have the bodies.
One solution could be to have a "bullpen" game.
"[Craig] Breslow is a candidate. [Jonathan] Aro threw three innings yesterday," said Lovullo. "He'll be down for a couple days. His next outing will be up to 45-50 pitches. Those are two guys we'll look to for length."
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, follow him on Twitter @IanMBrowne and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.