As of one month ago, Floyd Mayweather Jr. was tabbed to end his near decade-long retirement in an official boxing rematch with former dance partner Manny Pacquiao on Sept. 19 at The Sphere in Las Vegas. Now, he’s not so sure. The 50-0 boxing superstar raised major doubts about the legacy sequel during a meet and greet at the MCM store at Caesar’s Pace on Saturday, telling Vegas Sports Today that his return to the ring would be an exhibition and that it may not take place at the new Vegas venue.