Floyd Mayweather was seen among the audience at the Thomas and Mack Center where Manny Pacquiao and Jessie Vargas has vied for the WBO welterweight title.
This has set rumor mill of a rematch between Pacquiao and Mayweather into overdrive.
Speculation that Mayweather and Pacquiao would seek to fight again following their clash in May 2015, which became the most lucrative bout of all time, has mounted in recent months, reports said.
While Mayweather was not immediately available for comment, his arrival at the arena flanked by a large entourage could be seen by many as the opening salvo in the negotiations for and the PR campaign leading toward a rematch.
Pacquiao had earlier said he would like another chance to fight Mayweather, having complained of a lingering shoulder injury the first time around.
Mayweather is officially retired from boxing but his love of money and the spotlight is no secret, and the prospect of another payday that would likely top $100 million might be too much to turn down.
Previously, Mayweather has appeared to deliberately avoid watching Pacquiao fights and his arrival came as a major surprise. The 39-year-old formerly promoted Vargas, but no longer does so, and the timing of the entrance minutes prior to the main event made a clear statement that he was here to see one man – Pacquiao.
