That being said, look at this from Ausiello's Q&A with Schwartz and Fedak:
Question: I absolutely love Kristin Kreuk as Hannah on Chuck. Any idea how many more episodes she will be in this season? —Jeremy
Ausiello: Just one. Schwartz and Fedak confirmed that Kreuk’s arc will conclude on March 1. Meanwhile, Brandon Routh’s stay has been extended yet again, although Team um… Schwedak (?) wouldn’t provide an updated episode count.
I love Routh, despite not being on board with Sarah/Shaw.