The Hawk or Keith Rivers?

Picked up The Hawk to go with Laurinatis and Posluzny while Timmons takes a bye. Just realized that Rivers is a FA. Should I make the move oh mighty one?

I like Hawk's value better since he figures to be a three-down linebacker at least for this week as Chillar is likely to sit out again this week and now with the injury to Nick Barnett, Hawk may be a three-down linebacker for a good part of the remaining season. Rivers remains a two-down linebacker.