they have what 1 spot left?
Assuming they do sign Moore, as has been reported (is that one official), then yes, 1 spot. So, they use that on a center. That gives them JO, KG, Wilcox, and whoever they sign, all of whom can play significant minutes at center if needed.
And all of those guys can also play PF, along with Johnson, Bass, and Green.
Does it take more than 1 roster space to sign one more player?