Within the twominute warning period of either half , instant replay reviews can only take place if the replay assistant , who sits in the press box and monitors the network broadcast of the game , determines that a play needs review . Coaches may not use a coach ' s challenge . Coaches are not allowed under any circumstances to throw a challenge during the two minute warning . The official NFL rule book states no exceptions for plays that start before the two minute warning . The official NFL rulebook explicitly states that the two minute warning is at 200 and that there are no coaches challenges during that time . The penalty for throwing a challenge during that time is a 15 yard penalty . I believe the NFL knows more about their rules than any CBS announcer .