Time's up for two stars of 24. Penny Johnson Jerald and Sarah Wynter whose respective roles as Sherry Palmer and Kate Warner were pivotal last season will not be returning as series regulars for Day Three this fall, TV Guide Online has learned. A Fox spokesman refused to confirm the moves, but did caution that "it would be a mistake to infer from an actor's contract status what their participation in the show next year will be. For example, Xander Berkeley (George Mason) was hired as a series regular last year but his character was killed off in Episode 15." Yeah, that sucked for him.