Mayweather, 42, suggested he was in talks with UFC president Dana White, before appearing to confirm that he was again coming out of retirement next year with a post on Instagram.
“Dana White and I are working together again to bring the world another spectacular event in 2020,” he initially said on the social media platform.
He then posted a second picture, with the caption: “Coming out of retirement in 2020.”
Mayweather last fought Japanese kickboxer Tenshin Nasukawa in an exhibition boxing match.
That December 2018 fight was reportedly worth £7 million.
Mayweather had previously extended his perfect career record to 50 career fights unbeaten with victory over Conor McGregor, who had never previously boxed professionally.
The duel with the UFC superstar supposedly earned Mayweather a potential £230 million.