Celtics coach Joe Mazzulla said he wanted to “validate the roster” by starting Tillman, who had not played since March 6. “He can still impact winning,” Mazzulla said. “I just appreciate who he is as a person and I think you’ve got to validate the roster at times. I know that he can still help us, and there may be an opportunity where he does. I was grateful that we were able to give him that opportunity to be able to do that.”