If you give Doo a "rest," who's his replacement?
There isn't one and that's the issue. Everyone keeps talking about Hudson and Strickland. Hudson is having a career year to date and is probably due a lot of regression. He's issuing over 4BBs/9 and a sub 3 ERA isn't really that sustainable with his low K rate.
Strickland is clearly a head case, and has never really worked full innings before. Last season was his first acting as a closer and it wasn't exactly stellar.
Rodney would probably be next in line. Maybe he can do it for a couple weeks, but he is an implosion waiting to happen.