We already have Sully who is much better than Blair. No thanks.
Brandon Bass is also much better than Blair.
Blair is a 6'6" power forward who is a defensive liability. Not only does Brandon Bass have two more inches than Dejuan Blair, Bass also has two more ACLs. If you don't understand what I am saying, Dejuan Blair has a 0% chance of tearing his ACL because he doesn't have any. I would be very wary of a player who has both knee and conditioning problems, and Blair has at times ballooned up to 300-pound territory.
I think you should never hand this guy more than one guaranteed year on any contract.