Steven Espinoza

How serious is Floyd Mayweather about running it back one mo' gin with Manny Pacquiao? According to the top guy at Showtime Sports, he's serious as a heart attack ... as in DEADLY SERIOUS. TMZ Sports talked to Stephen Espinoza -- Prez of programming for Showtime Sports (and Conor McGregor's…

Floyd Mayweather is heading to Minnesota where he's set to meet with Showtime honcho Stephen Espinoza ... and the two will DEFINITELY be talking about a possible MMA fight. "It will be a topic of conversation," Stephen told TMZ Sports ... acknowledging Floyd's recent videos from inside an MMA cage…