Floyd Mayweather's two-year break from boxing gives Conor McGregor a chance of causing an upset in their controversial cross-code fight, says Carl Froch.
UFC champion McGregor faces legendary American boxer Mayweather, 40, in Las Vegas on 26 August in a boxing match that could earn both men $100m.
Four-time super-middleweight world champion Froch told BBC Sport: "Everyone expects Mayweather to win.
"But McGregor is 29. He is young, fit, hungry and confident."
Nottingham's Froch added: "I know McGregor is not a boxer; he's a cage fighter.
"But Mayweather could just come unstuck early on and might get caught with something. That's the big concern. It's a fascinating match."
Froch retired in July 2015, 14 months after knocking out George Groves to retain the WBA and IBF titles at Wembley Stadium.
He won 33 of his 35 fights, with 24 victories by knockout, but has no intention of following Mayweather's example by making a comeback.
"I'm 40 years old now and have been retired for three years," Froch said. "It's too long to be out of the ring and then come back at a competitive level.
"I'm nearly 14 stone and box at 12 stone. For me to boil myself to 12 stone would be dangerous for a start.
"I retired because I was feeling the pace. Boxing felt like work in my last couple of fights and it had never felt like work. I was doing something I enjoy. Doing something you are good at and enjoy doesn't feel like work.
"I've have had a fantastic career. I was a four-time world champion and retired on a high. To fill Wembley Stadium with a boxing event was unprecedented. It was the biggest fight post-war."