There aren't a lot of NBA caliber players in the D-League, especially guys with legit size. I never saw him playing, but I think the chances of him being better than Davis are basically non-existent. If this guy was any good, he'd be playing in the NBA already. Even if he wasn't that good but not a complete stiff either, he'd probably be playing in Europe.
Tall players do very well in the D-League statistically wise, because there's such a shortage of length. I remember Nick Fazekas. He put up very good numbers in the D-League, some stats guy said he would be a very productive NBA player and that Karl was crazy for waiving him. He went to the Belgian League, a 3rd tier league in Europe, and he isn't good enough to keep a job there.
I say the chances of finding a decent backup center in the D-League are very, very slim.