General Season 5 Spoilers:
According to Alias writer Breen Frazier, Syd is pregnant with Vaughn’s baby. Vaughn was investigating something with a rogue female agent. The female young trainee is going to be played by Rachel Nichols (The Inside), a male character is not cast yet. Greg Grunberg (Weiss) will leave. Mia Maestro (Nadia) and Lena Olin (Irina) will return for some episodes, but Melissa George won’t.
Source: Pittsburgh Post-Gazette
Nadia will not appear next season, not even in 1 episode. I’m hearing Sloane will be evil again. And Rambaldi is out … at least that’s the plan (mandate?). I hear that Dixon might be a little, um, well, evil this season … at least for a bit.
Source: Kristin on E!Online