Chael Sonnen is apparently leaving the door open to a return to the UFC. Chael Sonnen is also apparently leaving the door open to the possibility he won’t be able to pass the drug tests necessary to get back into the octagon.

U.S. Anti-Doping Agency (USADA) officials today revealed that Sonnen was recently subject to two different out-of-competition testing samples, which came as a bit of a surprise since the fan-favorite previously announced his retirement from the sport in June 2014.

A UFC official subsequently told MMAjunkie that Sonnen asked to be entered into the registered testing pool as he contemplates a return to competition. Athletes that retire from competition while still under UFC contract must give USADA at least four months notice before coming back to the sport in order to provide a testing window before stepping back in the octagon.

Sonnen (28-14-1 MMA, 7-7 UFC) walked away from the sport more than two years ago after he was caught in the middle of a dramatic drug-testing saga around UFC 175, where he was originally scheduled to fight Wanderlei Silva before having his opponent shifted to Vitor Belfort. He failed a pair of drug tests around the time of the contest, though, which resulted in a two-year suspension from the Nevada State Athletic Commission.

Sonnen, 39, was flagged for a total of five PEDs prior to UFC 175: anastrozole, clomifene, human chorionic gonadotropin (hCG), human growth hormone (HGH) and recombinant human erythropoietin. The first failed test prompted the UFC to pull him from the fight, after which he publicly retired from the sport. The second positive test, which revealed the presence of noted PEDs HGH and EPO, triggered the termination of his relationship with the UFC and FOX, where he served as a host of FOX Sports 1’s weekly “UFC Tonight” news program. He now works as an analyst for ESPN.

Shortly after retirement, Sonnen opened up about PED use on his podcast, “You’re Welcome with Chael Sonnen.” The nearly 20-year MMA veteran said he didn’t regret his actions.

“I’m not going to apologize because I’m not sorry,” said Sonnen. “I’m a consenting adult; I knew exactly what I was doing. This was a premeditated decision. If I go jump in my car and I back up and I hit my neighbor’s garbage cans, I’m sorry for that. This was a calculated decision. I made the decision, and I’ll live with it. That’s it. I wouldn’t make any excuses about it.”

In typical Sonnen fashion, the outspoken entertainer confirmed he was tested by USADA late last week, but seemed less optimistic when asked if a that mean a comeback was imminent.

“Not if the test is as good as I remember it being,” Sonnen told MMAjunkie, declining further comment for the time being.