Browns center Alex Mack played Sunday's game with what he thought was the flu, but turned out to be appendicitis. Mack underwent a successful emergency appendectomy on Monday afternoon. He will rest through the bye weekend and his availability for the Oakland game Oct. 16 is uncertain. "He's tough as nails because he was feeling a little queasy during the game, too," said right tackle Tony Pashos. "I was over there last night watching Sunday night football with him and he was talking about some issues then, too, and I was like 'maybe it's just something you ate.'"