Mayweather signed off his professional career with a points win over Andre Berto in September 2015 to take his record to a perfect 49-0.
But the former five-weight world champion, who turns 40 next month, has in recent months been linked with a so-called 'super fight' in a crossover encounter against McGregor.
The Irishman insists his next fight will be in a boxing ring and called out Mayweather, branding him 'scared'.
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Mayweather is keen for the bout to go ahead but has no timescale.
He said on Sky Sports 1: "Most likely the fight between me and Conor McGregor will happen.
"That's the only fight that will get me back in the ring. He's going to do a job on his side and we are going to do a job on my side and hopefully all the fans in the UK come over and support me.
"I don't know (when it will be), I need to communicate with my team, the fight hasn't been made yet, but it is all about entertainment so hopefully we can make it happen."
