Mirko Filipovic might be officially retired from MMA, but it appears “Cro Cop” will soon be formally suspended from competing in the sport, as well.

UFC officials today announced the veteran heavyweight is the first athlete to be flagged for a potential violation of the company’s new anti-doping policy, which is administered by the United States Anti-Doping Agency (USADA). The substance found in Filipovic’s system was not revealed.

Here’s the statement:

UFC announced today that a scheduled bout between Mirko Cro Cop and Anthony Hamilton in Seoul, South Korea has been canceled. The U.S. Anti-Doping Agency (USADA) has notified both Mirko Cro Cop and UFC that he has been provisionally suspended at this time due to a potential Anti-Doping Policy violation.

USADA, the independent administrator of the UFC Anti-Doping Policy, will handle the results management and appropriate adjudication of this case involving Cro Cop. Additional information will be provided at the appropriate time in the process.

Filipovic (31-11-2 MMA, 5-6 UFC) announced his MMA retirement – making no mention of a failed drug test – earlier this week. UFC officials today said his planned UFC Fight Night 79 bout with Anthony Hamilton (14-4 MMA, 2-2 UFC) has been canceled. Rather than seek a replacement opponent on short notice, Hamilton instead will be be rebooked on a later card.

UFC Fight Night 79 takes place Nov. 28 at Olympic Gymnastics Arena in Seoul. The entire event streams on UFC Fight Pass. “Cro Cop” vs. Hamilton was slated as the night’s co-headliner. A replacement bout hasn’t been announced.

In an announcement posted on his official website on Tuesday, Filipovic said a shoulder injury forced him to pull out of the fight.

“I tried to save a shoulder injury and repair in all possible ways: daily therapy, injections of blood plasma and various cocktails of drugs but didn’t work out,” the 41-year-old Croatian wrote. “The only cure would be a break of two to three weeks, and that I could not afford in the midst of final preparations. By daily trainings the injury gets worse. Part of the muscle is snapped, the shoulder is filled with a lot of fluids, and the great danger is that tendon ruptures and then go to operation again.”

“Cro Cop,” a former star in the now-defunct Japanese fight promotion PRIDE, made a long-awaited UFC debut in 2007 but went 1-2 and made a quick departure. He then returned in 2009 and went 3-4 and announced his retirement, but it was short-lived, and he returned to kickboxing and then MMA. In April, he joined the UFC for a third stint and earned a “Fight of the Night” bonus for his TKO win over Gabriel Gonzaga. It then led to the booking against Hamilton.

However, injuries – a constant nuisance in the second half of his career – again became an issue in recent years.

After a decorated run in combat sports, his career now carries an unfortunate footnote. The UFC launched its anti-doping initiative back in July, and though more than a hundred fighters had undergone tests, none had failed a USADA-administered drug test prior to Filipovic.

For more on UFC Fight Night 79, check out the UFC Rumors section of the site.