By Steve Kim

Since 2013, Showtime has been the exclusive home of former five division world champion Floyd Mayweather (50-0, 27 KOs), beginning with his fight against Robert Guerrero.

Time and time again he promised never to fight again, but then Mayweather unexpectedly came back the ring to a high profile pay-per-view fight with UFC superstar Conor McGregor, which took place in August at T-Mobile in Las Vegas, and saw him win a with a tenth round stoppage.

After his victory over McGregor, the 40 year old veteran promised that he was now calling it quits, for good, on his Hall-of-Fame career.

But Mayweather has made these types of promises in the past, on more than one occasion, and ultimately came back.

So is this really the last we've seen of Mayweather inside the ring?

"I don't know how he tops this one," said Stephen Espinoza, the Executive V.P. and G.M. of Showtime Sports, to BoxingScene.com. "I understand completely his full sincerity of his intended retirement, how this would be so intriguing that he would come out."

In other words, while there were a lot of other fights against boxers that were lucrative, none brought to the table what McGregor did with his success in the UFC. Is there another proposition that would interest Mayweather in the future?

"I don't know what's left in his back of tricks at this point," said Espinoza. "You keep upping the ante, I'm not sure how you keep topping yourself when you've done the two biggest pay-per-views of all-time."

For the moment Mayweather appears to be focused on his numerous business ventures, like his TMT clothing like and his promotional company - which handles fighters like Andrew Tabiti, Badou Jack, Gervonta Davis, Ronald Gavril and numerous others.

Steve Kim is the news editor for BoxingScene.com.