There are several layers here. First, the question: is he telling the truth? It is not out of the realm of possibility Mayweather is going for the headline to overshadow the superfight taking place tonight between Canelo Alvarez and Gennady Golovkin.
But this fight does make a lot of sense for both of them. As Mayweather put in his Instagram post, this would, by all expectations, be another nine-figure payday for him. As boring as most believed the first fight to be at least four years after it should have happened, Pacquiao is still the biggest name Mayweather can realistically return to fight. This is the biggest money-making chance for Pacquiao as well.
If this fight does take place, it would be a major risk for Mayweather. Neither are what they once were, but Pacquiao was very impressive in his last fight against Lucas Matthysse.
I, for one, am completely down for witnessing the best two boxers of the past 20 years facing off one more time.