The Bulgarian striker is expected to complete his £4m move to the Cottagers on Friday after passing a medical with the Premier League club on Thursday.
However, Ferguson reveals that there could be a late twist in the transfer saga.
"It wouldn't surprise me if he's at Tottenham," he said. "I don't think he's certain to go to Fulham, put it that way. I said last year he'd be leaving at the end of the season.
"I don't know what's happened. He's not gone yet. I don't know anything about it. There's not been any contact whatsoever from him."
"According to Fiorentina he was supposed to be on a plane, and we thought that too," he continued. "We thought he was in Italy.
"It's turned out he's not in Italy. He could be anywhere to be honest. I have no idea where he is."
Berbatov joined United from Tottenham in 2008.