Showtime Boxing's broadcast analyst, Steve Farhood, believes at this point former five division world champion Floyd Mayweather Jr. would struggle against the very best fighters in the welterweight division.

Mayweather, 40 years old, snapped a two-year retirement back in August - to fight UFC superstar Conor McGregor, who was making his pro debut.

McGregor did well in the first three to four rounds, but he was broken down and stopped in the tenth round.

The victory over McGregor raised Mayweather's record to a perfect 50-0, which allowed him to break the undefeated record of heavyweight great Rocky Marciano.

Mayweather, who retired following the contest, received a lot of heat for the fight.

Most fans and experts felt that he should have faced a top level fighter to reach a 50-0 record.

But Farhood explains that there simply wasn't enough money to face a top level boxer - when Mayweather stood to earn well over $100 million for a much easier fight against McGregor.

"I think he’s in an unusual position and I say that because the average fighter would kill for a $30 million dollar pay day, that’s money that Keith Thurman, Shawn Porter or Terence Crawford could very well never see, but for Floyd, a $30 million dollar pay day just doesn’t turn him on. The McGregor fight was perfect for him because he was basically against a guy who had never fought before and he was handed somewhere between $100 and $200 million dollars. That’s not going to happen against any boxer we know," Farhood told On The Ropes Boxing Radio.

And if he did take a pass on McGregor and fought a boxer on the level of a Keith Thurman, Terence Crawford or Errol Spence - Farhood believes the former pound-for-pound king would struggle in the right.

"I think he probably struggles against the very best, against Keith Thurman, Terence Crawford or Errol Spence. I don’t think it’s as easy as it used to be. Floyd is a fighter who relies a lot on reflexes and on his athletic ability, and just a very small diminishment in his skills could really affect him. We saw with Oscar De La Hoya and Roy Jones, when these fighters who are superior athletes lose that half second of timing, it can bode very badly for them," Farhood said.

"I think we may be at that point with Mayweather — it’s a little difficult to tell strictly from the McGregor fight, but he is forty and there’s nothing to say that he couldn’t lose that half second in reflex time, and I think there’s a good chance that that’s happened."