Undefeated Bute will put his IBF super-middleweight title on the line in Nottingham on May 26.
While Calzaghe concedes that the odds are in Bute's favour, he thinks that the 32-year-old Romanian may be made to regret agreeing to fight in his opponent's hometown.
"Bute's definitely the favourite but home advantage does count for a lot," Calzaghe told The Sun.
"If Froch can drag him into a war and make it a toe-to-toe affair, I can see the crowd spurring him on to the win.
"All I would say is that Bute wouldn't have come to England unless he was confident. It's going to be a tough, tough night, but I think Froch has got a chance."