Well, I though Mutumbo's career was over last year. That's why Houston didn't resign him.
Was O'Bryant better than the Mutumbo of three years ago? On offense, yes. Defensively, of course not. Is O'Bryant better defensively than the current Mutumbo? My guess is, yes.
Maybe they can activate Clifford Ray and get ten minutes a game out of him. He's probably not that much older than Mutumbo, whose real age is rumored to be more than 42.
But no, Clifford has his ring (two actually, one as a player, one last year) so he probably wouldn't be interested.