It's probably not much of a coincidence that Floyd Mayweather picked Sept. 15 to make a shocking announcement. Gennady "GGG" Golovkin and Canelo Alvarez will be fighting in Las Vegas for the unified middleweight title Saturday night, but the ostentatious Mayweather appeared to want to steal the spotlight by dropping the bombshell that he will have a rematch to the 2015 megafight with Manny Pacquiao later in 2018.

Mayweather took to Instagram with the simple comment: "I'm coming back to fight Manny Pacquiao this year another 9 figure pay day on the way."

Mayweather defeated Pacquiao by unanimous decision in a fight that was more tactical than entertaining. There have been clamorings for a rematch ever since, with the chorus growing louder after learning that Pacquiao had fought with a shoulder injury.

The financial aspect also can't be overlooked, as Mayweather's estimated windfall was between  $220-$230 million, while Pacquiao earned roughly $150 million.

The rematch is not expected to generate the same level of interest, but it seems certain to be one of the biggest boxing events of the year.

GettyImages-472121524 Floyd Mayweather announced he is fighting Manny Pacquiao in 2018. Photo: JOHN GURZINSKI/AFP/Getty Images

Pacquiao is coming off a win over Lucas Matthysse of Argentina on July 15, capturing the WBA welterweight title. Mayweather last fought in August 2017 in a roundly dismissed boxing match against UFC fighter Conor McGregor.

Mayweather reportedly earned roughly $300 million for the McGregor fight, which was at the light middleweight class of 154 pounds.

Both Mayweather and Pacquiao have the name recognition that might help many overlook their age. Mayweather is 41 years old and Pacquiao will turn 40 in December.

However, both boxers may still have something left in the tank. Despite facing an inexperienced and unpolished opponent in McGregor, Mayweather showed that he hadn't lost his sharp boxing skills and another long layoff probably won't slow him down. With a record of 50-0, and having defeated the best in the talent-rich welterweight division, Mayweather is one of the all-time greatest boxers and certainly one of the best defensive specialists the sport has ever seen. 

Pacquiao (60ā€“7ā€“2) defeated a quality boxer in Matthysse and he seemed to clearly defeat Jeff Horn in a July 2017 fight that was controversially ruled a unanimous decision loss for the Filipino icon. While most would say Pacquiao is past his prime, he has shown great resiliency in the later years of his career. 

Yet, another fight between Mayweather and Pacquiao could still be more of the same. Mayweather will no doubt make outlandish comments to boost interest, while Pacquiao will take the more unassuming approach. When the two step into the ring, Mayweather will effectively dodge punches and land just enough to win rounds in another probable unanimous decision.