As with the argument for signing another wing... why's Diogu going to sign here if he thinks we're going to re-sign BBD as well? He's a young guy who you'd think is looking for the opportunity to prove himself, it he's only making the vet minumum or LLE anyway, he's much better off going to a young, rebuilding club where he's got the chance to either compete for a starting spot or at least be the first big off the bench. Why would he come to Boston to fight for maybe 5/10 minutes a night, and likely 0 minutes a night if BBD returns?
If he comes to Boston, they re-sign BBD, and he doesn't get off the bench, he's done in the League.
You go after Diogu (and he wants to come here) if you've given up on re-signing BBD.
Besides, that 5th-big role is going to go to Swift, we all know how inevitable that is.