Mayweather, the former five-weight world champion, said he was hanging up his gloves in 2017 after defeating UFC star Conor McGregor in a boxing match in Las Vegas. "Boxing is a very, very brutal sport".
Mayweather already reneged on his retirement once to take on the Irish MMA fighter, with the unbeaten Michigan-man now again considering swapping the ring for the octagon. He continued: "You have got to know when to hang it up".
Mayweather took part in a three-round exhibition bout against Japanese kickboxer Tenshin Nasukawa a year ago, winning by first-round TKO. "I had a great career", he said Saturday.
The 42-year-old made the announcement on his Instagram account, and also said he is working with UFC boss Dana White to "bring the world another spectacular event". And in 2018, he was also dropping hints regarding a potential rematch with Manny Pacquiao - and then later stated that he wasn't interested in a second fight. It was just time for Mayweather to feel the media spotlight again.
Mayweather retired in 2015 after beating Andre Berto, only to return to fight McGregor on August 26, 2017, at T-Mobile Arena in Las Vegas.
The Irishman is set to return to the UFC early next year and another fight with Mayweather could be one of the biggest draws in combat sport history.
A lot of people online are making guesses about who Mayweather will choose to fight next if he really is coming out. "I make great money doing exhibitions - between $10 [million] and $30 million", he said. There are plenty of fighters Mayweather could go up against right now but it's clear that most fans want the Pacquiao rematch.
The former pound-for-pound king was recently courtside at an National Basketball Association game with UFC President Dana White, and claimed that something big was coming in 2020.