Undefeated boxing great Floyd Mayweather Jr. wants to jump back in the ring, this time to face UFC Champion Conor McGregor, and he’s willing to offer McGregor a $15 million payday to accept the challenge.

Mayweather, who only hung up his gloves two years ago, is still considered one of the best fighters of all time and remains undefeated in his professional career. But Ultimate Fighting Championship title holder McGregor, ten years junior to Mayweather, also has a long list of wins including titles in three separate weight classifications.

For several weeks, a bout between Mayweather and McGregor has been discussed and the UFC mixed martial artist has taken the talks seriously enough to secure a California boxing license.

But thus far money is the real sticking point, SportingNews.com reports.

During a recent appearance on ESPN’s “First Take,” Mayweather said he has offered McGregor $15 million upfront for the fight and thinks that the event might bring in an over $100,000 million take.

According to Fox Sports, the biggest payday McGregor has had in the past was $3 million.

But the boxing champ says that McGregor can’t expect much more cash for the fight because he’s never earned that much in his life.

Look for Mayweather’s comments about half way through the clip below…

Follow Warner Todd Huston on Twitter @warnerthuston or email the author at igcolonel@hotmail.com.