After averaging 14.4 points and 8.1 rebounds per game up until the 2015 NBA All-Star Weekend, Sullinger was ruled out indefinitely after X-rays on February 19 revealed a stress reaction in his left foot. Three days later, he was ruled out for the rest of the season after further medical evaluation determined that Sullinger had sustained a left metatarsal stress fracture. However, in a surprising move, Sullinger returned to action on April 3 against the Milwaukee Bucks. He entered the game four minutes into the third quarter, missed both his shots and didn't return as part of a gradual effort to improve his stamina.