The United States Anti-Doping Agency (USADA) has flagged UFC heavyweight Ben Rothwell for a potential violation of the promotion's anti-doping program.
The UFC announced on Tuesday it had been formally notified of Rothwell's potential violation. The incident stems from an out-of-competition test administered on Feb. 6.
Per standard policy, USADA did not offer further details on the potential violation.
Rothwell (36-10) was expected to face Fabricio Werdum at UFC 211 on May 13 in Dallas. Tuesday's news will likely scrap those plans.
The 35-year-old Rothwell hasn't fought since a five-round decision loss to Junior dos Santos last April. He was supposed to fight Werdum at UFC 203 in September, but was forced to withdraw with a knee injury.
In 2013, Rothwell served a nine-month suspension after testing positive for elevated levels of testosterone after knocking out Brandon Vera at UFC 164 in Milwaukee. At that time, Rothwell had been approved to use testosterone-replacement therapy (TRT), which has since been widely banned in combat sports, but his levels were above the allowed limit.