Carls John De Tomas suffered a second round submission loss to Alex Perez on the preliminary card of UFC Fight Night Fresno.

The fighter was also recently notified by the United States Anti-Doping Agency (USADA) about a potential violation. The failure came from an in competition sample collected by USADA on the day before the event took place.

Here is a statement from the UFC on the matter:

The UFC organization was notified today that the U.S. Anti-Doping Agency (USADA) has informed Carls John de Tomas of a potential Anti-Doping Policy violation stemming from an in-competition sample collected following his weigh-in on December 8, 2017.

Although de Tomas is no longer under contract with UFC, USADA, the independent administrator of the UFC Anti-Doping Policy, will handle the results management and appropriate adjudication of this case, as it relates to the UFC Anti-Doping Policy. Under the UFC Anti-Doping Policy, there is a full and fair legal process that is afforded to all athletes before any sanctions are imposed. The California State Athletic Commission (CSAC) also retains jurisdiction over this matter as the sample collection was performed the day before de Tomas’ bout at UFC Fight Night: Swanson vs Ortega in Fresno, CA. Accordingly, USADA will work to ensure that the CSAC has the necessary information to determine its proper judgment of de Tomas’ potential anti-doping violation.

Additional information will be provided at the appropriate time as the process moves forward.

There is no word yet on what kind of substance De Tomas potentially failed for and what kind of punishment the fighter could be facing.