Angel

In an Interview with Joss Whedon from the Premiere issue of the Angel Mag, he has this to say about Sarah’s return :

Have you talked to Sarah Michelle Gellar about the possibility of her making guest appearances ?

Joss : Yes, I have. And so has David [Boreanaz]. She’s always been very open to the idea- she’s probably the busiest of all, but she’s talked to [WB entertainment president] Jordan [Levin] about it. She’s someone who’s said from the start, "If I have the time, if the schedule is there, we’ll do it, count me in." We’re hoping she’s available, oh, sweeps time. But we can’t control that—neither can she.