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First Rob Lowe, now Calista Flockhart. They're breaking up that old Walker clan of ours. In short, Calista Flockhart will be on fewer episodes next season of Brothers and Sisters. So, if Rob is gone completely, and Calista is doing less shows, are the McCallisters even going to be living in California anymore?

We now know why Rob Lowe made the decision he did. His role is integrated into the Walker family through Calista's character, Kitty. If she was asking for a reduced presence, the ripple effect was clearly less screen time for him. Hence, his decision.