Why would James Singleton be worth the wait?

Restricted free agent forward James Singleton will continue to take his sweet time before deciding whether to take the Mavs' qualifying offer of a little more than a million bucks. Who cares about a guy who would be buried on the bench behind Dirk Nowitzki, Shawn Marion, Drew Gooden, Tim Thomas and perhaps Kris Humphries? Well, Rick Carlisle, for one. Singleton's impact on the Mavs isn't limited to what he does when he gets playing time, although there's room on the roster (figuratively, if not literally at the moment) for a relentless rebounder/defender who thrives on doing dirty work. Carlisle loves the energy and intensity that Singleton provides on the practice court. Because of that, the Mavs would be a better team with Singleton even if he can't crack the rotation on a regular basis. Is that worth the wait and a million bucks? Absolutely, as long as Cuban is writing the check.