With just one ping to Manny, this match is possible. He's the one that just have to make an action to trigger the fight.
This is possible but least likely to happen, Mayweather is already rich, he has the money and he can fight to an exhibition game and make millions.
He doesn't need to risk his undefeated record, he also wants to have a legacy in the sports of boxing, and even we don't like his style but the record speaks itself that he is a good fighter.
How about $250-$300 million?? for just one fight and possible to win it against Manny? Will he turn it down? Floyd doesn't concern about his legacy whatsoever, he is after money fights and with the way he live his life, he can't sustain that if there is no money coming it.