Nick Santora on Sarah Wayne Callies' Return

"So I am glad people are excited about Sara coming back. If you go back thru Season 3 you’ll see that we intentionally did several things that would allow us to bring the character back if it was feasible production-wise. We saw an opportunity, the talented SWC was available and now we are going to have a fun time making a 4th season. Thanks for supporting the show.

Best, Nick Santora."

Source: PBreakFans