"I think his odds are a lot more tougher than mine," Buster told TMZ Sports.
"Conor is no boxer ... he has no boxing skills."
Buster says Conor's only shot is hitting Floyd with a "Hail Mary punch" -- but he expects Floyd to flat-out dominate.
FYI, Douglas was a 42-to-1 underdog when he knocked Tyson out.
Right now, Conor's about a 4-to-1 dog ... but over 90 PERCENT of bets are being put on him to upset.