The U.S. Anti Doping Association's PED testing keeps working for the UFC, although it's to varying degrees of success, as more fighters are being caught, but others exonerated -- sort of.

Chad Mendes was the latest UFC fighter to be flagged for a potential violation under USADA. It was revealed Friday night that the three-time UFC title challenger failed an out-of-competition test. Mendes has not competed since losing to Frankie Edgar in December at a TUF Finale event.

The substance in which Mendes tested positive for was not identified, but the UFC released a statement on the matter.

"The UFC organization was notified today that the U.S. Anti-Doping Agency (USADA) has informed Chad Mendes of a potential Anti-Doping Policy violation stemming from an out-of-competition sample collection.

USADA, the independent administrator of the UFC Anti-Doping Policy, will handle the results management and appropriate adjudication of this case. It is important to note that, under the UFC Anti-Doping Policy, there is a full and fair review process that is afforded to all athletes before any sanctions are imposed. Additional information will be provided at the appropriate time as the process moves forward."

While USADA continues to catch offenders, it also has been catching 'offenders.' Yoel Romero and Tim Means both proved to the agency that they took a supplement that wasn't supposed to have a banned substance in it, but was tainted. Both men still received six-month suspensions, with Means' being retroactive to February 3, and Romero's on January 12.

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