As if the Floyd Mayweather vs. Manny Pacquiao fight couldn't be more of a debacle, it takes yet again another surprising turn.

According to Dan Rafael of ESPN, "Mayweather took an intravenous injection of saline and vitamins that was banned under World Anti-Doping Agency guidelines." That same report also noted that the injection was made before the fight occurred. This confuses and angers many boxing fans because Pacquiao was not allowed to take a painkiller prior to the fight for his hurt shoulder.

It was later learned Pacquiao had a torn rotator cuff injury. An injury he has since had surgery for.

The report noted that a total of 750 milliliters of the saline and vitamins was injected into Mayweather after the weigh-in. That's an extremely significant amount because the limit is just 50 milliliters per six hours. That 50 milliliter limit is also the standard for Olympic style boxing. Mayweather's only loss came at the Olympics in 1996.

Mayweather is still scheduled to fight Andre Berto this weekend at the MGM Grand. For years some boxing fans have criticized Mayweather because they believe he has gotten away with things, and he constantly fights at one location. It was also reported that the United States Anti-Doping Agency did not inform the Nevada boxing commission until May 21, 19 days after the fight had occurred. It appears as if Mayweather may have had "ring field advantage" against Pacquiao on May 2.

Mayweather has not yet responded to any of the reports.

Pacquiao's desired painkiller is not banned nor is illegal in the boxing world, but it was denied for the Filipino star because of the timing of the request.

This whole ordeal may not be over just yet. As we all remember fight negotiations between Mayweather and Pacquiao had been constant since 2009. Numerous reasons blocked the fight such as Mayweather not wanting to face Pacquiao, Pacquiao's infamous "loss" to Timothy Bradley, and especially steroid talk. As a matter of fact Mayweather even accused Pacquiao of using banned substances resulting in a lawsuit by the Pacquiao team. Could we see another lawsuit looming?

Pacquiao, who is currently healing from shoulder surgery, does not have a scheduled fight, but his promoter, Bob Arum, has already told the media he is open to facing Amir Khan next. Many fans would have wanted to see a Mayweather vs. Pacquiao rematch, but with this new evidence, that doesn't appear likely at all.

This isn't the first time Mayweather has been accused of using banned substances. According to boxing journalist Gabriel Montoya, Mayweather tested positive for performance enhancing drugs three times in 2012, but the USDA covered it up. Nothing has been 100 percent proven in a court of law yet, but there certainly seems to be a lot of smoke around Mayweather.

Follow Damon Salvadore on Twitter @DamonSalvadore1