White told reporters after the UFC Fight Night 48 on Saturday he think's he's close to having the deal finalized.
"Yeah it's complicated, but I think we're close," he said.
Carano, the former face of female MMA, hasn't fought since 2009.
The idea was to have her signed and ready to go for a fight against Ronda Rousey, the undefeated current -- and first -- UFC Women's Bantamweight champion, in December.
White said he's not sure if that plan is still on the table.
"I don't know. I had plans, but now I don't know," he said. "We have to see how this thing plays out. Like I said, I wouldn't know more about that until September. First week of September I should have more answers."