Mayweather captured the WBO welterweight title on June 2 when he beat Manny Pacquiao in Las Vegas, and holds the WBA and WBC titles in the same division.
However, he also holds the WBA and WBC titles at junior middleweight, which contravenes WBO regulations.
According to WBO legislation, a fighter cannot hold world titles in multiple weight classes and to remain the WBO champion at 147 pounds, he would need to vacate both his titles at 154.
The previous time either of the titles at 154 were defended was nearly two years ago, in September 2013.
As a result, the WBO has indicated that Mayweather "will likely" be stripped of his lone WBO title.
If that is the case, Timothy Bradley will become the full champion, after he captured the WBO interim title with a victory over Jessie Vargas last weekend.