Edmonton’s UFC 215 card has lost one of its marquee fights as the heavyweight bout between former champion Junior dos Santos and Francis Ngannou has been pulled due to a potential anti-doping violation against the former title holder.

Dos Santos’ violation potentially occurred on an out-of-competition test conducted on August 10th, USADA revealed on Friday.

 UFC said in a statement that due to the proximity of the event, Dos Santos has been removed from the card and that they are currently seeking a replacement.

Here is the entire UFC statement:

The UFC organization was notified today that the U.S. Anti-Doping Agency (USADA) has informed Junior Dos Santos of a potential Anti-Doping Policy violation stemming from an out-of-competition sample collected on Aug. 10, 2017. Because of the proximity to Dos Santos' upcoming scheduled bout at UFC 215 in Edmonton, Canada against Francis Ngannou, Dos Santos has been removed from the card and the UFC is currently seeking a replacement.

USADA, the independent administrator of the UFC Anti-Doping Policy, will handle the results management and appropriate adjudication of this case involving Dos Santos. 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. Additional information will be provided at the appropriate time as the process moves forward.