With Floyd Mayweather retirement at hand, who's best pound-for-pound fighter?

LAS VEGAS - The king is dead. Long live the king.

After Saturday night's welterweight title fight against Andre Berto, Floyd "Money" Mayweather will hang up his gloves, settle into his easy chair and fade away from the sport that made him rich and famous beyond his wildest dreams. At least that's how he's playing it. And unless or until he changes his mind, the sport will have to forge ahead without the pre-eminent ring showman of this era.

Say what you will about Mayweather, he has been very good for the sport - for those who compete in it, those who run it, those who write about it and those who follow it. He has made his fellow fighters more money than ever before. As Mayweather said this week when asked if anyone will ever approach his records in terms of generating cash, he said, "Honestly, it's hard. I don't want to sit here and say, 'hell no.' But is a fighter ever going to make $300 million in 36 minutes again? We'll just have to see."

Besides being it's biggest cash cow, Mayweather has been the sport's undisputed best pound-for-pound fighter for years and deservedly so. Nobody has been able to figure him out, though not everybody has had a fair chance. Sure his hit-and-not-get-hit style is unappealing to most, but that's the only way he could have survived this long and still be fighting at such a high level. He wants to get out with his brain still intact, and who can blame him?

But after Saturday he will be gone and boxing's pound-for-pound lists will have to be reworked. Who will be the new No. 1? Andre Ward, who might be No. 1 if he actually fought more than twice in three years, is not on the list because of his inactivity, much of it not his fault after being embroiled in a contract squabble with the late Dan Goossen for a few years. But Roc Nation needs to get him out there. He's be 32 in a few months and his prime years are slipping away.

That being said, here are five active fighters who stand the best chance of taking over the No. 1 spot, in alphabetical order:

Terence Crawford: The boxing writers' 2014 fighter of the year is Mayweather-esque with his skills as a boxer. He has great quickness with his hands and feet and a high ring IQ, and his power is a level or two above Mayweather's. But he's in the junior welterweight division, and most of the elite fighters in that division have moved up. If Crawford (26-0, 18 KOs) wants to get the fights he needs and has been unable to secure, he might want to consider a move up to 147 to have a greater selection of opponents. Up to this point, only Yuriorkis Gamboa, who Crawford systematically broke down and knocked out in June 2014, could be considered a high-quality opponent. His promoter, Top Rank, knows it has a true superstar in Crawford, but needs to work harder to get him quality opponents. Dierry Jean, who Crawford will fight on Oct. 24, is not one of them.

Gennady Golovkin: The Kazakh destroyer has mowed down everyone in his path, using a patient, ring-smart style to study his opponent through the first few rounds, then zeroing in for the kill and eventually knocking him out with those heavy hands. He has done that for 20 fights in a row. Like most Eastern Europeans, GGG (33-0, 30 KOs) learned how to box before he learned how to punch, so he can do it all. He has also had trouble getting quality opponents, but in this case, it's because nobody wants to become his next victim. Ward has been calling Golovkin out recently, but GGG wants to unify the middleweight division first, which would mean Cotto and/or Canelo first, though it would probably have to be at a catchweight for either. If GGG can take out another power puncher in David Lemieux on pay-per-view Oct. 17, he will emerge as a top 2 P4P.

Roman "Chocolatito" Gonzalez: The nasty Nicaraguan is fighting Brian Viloria on the Golovkin-Lemieux card on Oct. 17, which makes this pay-per-view event worth the money. The lightest-weight boxer on this list, the flyweight champ has a knockout punch second to none. Chocolatito (43-0, 36 KOs), like everyone else on this list, is a multi-dimensional fighter, who was discovered and learned his craft from Nicaragua's greatest fighter, the late Alexis Arguello. His title fight against highly respected veteran Viloria at Madison Square Garden should be a classic.

Wladimir Klitschko: Until someone can knock Dr. Steelhammer off his heavyweight throne, he has to be on this list. Will undefeated Tyson Fury be the one to do it on Oct. 24? Highly doubtful. Klitschko (64-3, 53 KOs) has held a heavyweight title for nearly a decade now, and won most of his fights by knockout. He is a highly skilled boxer and probably the most intelligent fighter on this list. At 39, he can't be around much longer, can he? The Ukrainian star has been the second-longest reigning heavyweight champion of all time, behind Joe Louis. He will be on this list until he loses.

Sergey Kovalev: "Krusher" is the third Eastern European on the list, and the Russian, like his counterparts GGG and Klitschko, learned to box first and punch later. Kovalev showed his ring IQ by often outsmarting Bernard Hopkins, who can match wits with anyone in the world. Unfortunately for Kovalev, he was matched up with a weak Nadjib Mohammedi in July. We won't know how scary good the Russian is until he's put in the ring with someone like Adonis Stevenson, or Andre Ward. And don't be fooled by his smile when he shows up on TV watching someone else fight. Kovalev is mean with a capital M. Ask B-Hop, who stuck his tongue out at Kovalev at the beginning of the 12th round of their fight. Kovalev nearly took off Hopkins' noggin, head-hunting with a vengeance the rest of the way. Even that couldn't stop Hopkins, who's never been stopped. But with 25 of his 28 wins by KO, Kovalev is the real deal.

Honorable mention: Canelo Alvarez, Timothy Bradley, Manny Pacquiao, Guillermo Rigondeaux