McClure explained the decision before Tuesday's game, saying the 26-year-old's versatility as a left-hander would bolster the bullpen. With Rich Hill on the disabled list, Andrew Miller has been the lone southpaw in the bullpen, thus increasing the urgency for Morales' return.
"We're fortunate to have five really good starters," McClure said. "Franklin understands the decision. He's a gamer. The fact that he's a lefty also played a factor in the decision.
"I still think he's got a future [starting]."
Since making his first start on June 17 –– in place of Josh Beckett, who was battling shoulder inflammation –– Morales has thrived, posting a 2-1 record to go along with 33 strikeouts.
Clay Buchholz will be scheduled to start against the White Sox on Thursday.