By Alek Arend The Chicago Bulls might be without a key member of their rotation in Game 5 vs. the Bucks. Alex Caruso has officially entered concussion protocol. Caruso left Sunday’s Game 4 after being on the receiving end of an inadvertent hit to the face. He exited the court with a bloody nose and eventually went to the locker room. He didn’t return to the game. Facing playoff elimination this Wednesday night, the Bulls might not have one of their toughest players on the court. “I think there was enough there that they had some concerns that it was [a concussion],” Donovan said after the game…