Lee suffered a mild knee sprain in the fourth quarter of Wednesday's loss to the Memphis Grizzlies in Boston. He warmed up before Friday's game against the Cleveland Cavaliers, but was unable to go. After Saturday's game, the Celtics are off until Milwaukee visits on Tuesday night, giving him additional time to recover.
Neither Rajon Rondo (ACL rehab) nor Kelly Olynyk (sprained right ankle) traveled to Milwaukee either. Boston wraps up the second night of a back-to-back -- and plays its 19th game in 31 days -- on Saturday evening.