Yoel Romero can be back in the Octagon soon.

The UFC middleweight contender was handed a six-month suspension by USADA on Monday, the UFC's anti-doping partner announced on its website.

The news of a shorter suspension than otherwise thought was first reported by MMA Fighting's Ariel Helwani on Monday morning.

In December, Romero tested positive for a substance called Ibutamoren, a growth hormone secretagogue. The National Center for Biotechnology Information describes the substance, which is prohibited under the UFC's anti-doping policy, as stimulating growth hormone release "through a pituitary and hypothalamic receptor."

Romero, 38, denied knowingly taking the substance and has claimed all along that it came from a contaminated substance. USADA said in its release that it had Romero's supplement tested and Ibutamoren did indeed come up, even though that banned substance was not listed on the label.

"This case clearly demonstrates some of the dangers inherent to supplement use," USADA's Special Advisor on Drugs and Supplements Dr. Amy Eichner said in the release. "When considering whether to incorporate supplements into a training plan, it is vitally important that athletes exercise the upmost care in order to avoid making a decision that could endanger their eligibility, reputation or general health and wellness."

The substance that Romero tested positive for has not been known until now.

Confident that he had not knowingly taken a performance-enhancing drug, Romero decided to go to appeal USADA's sanctioning and take the case to arbitration. Sources said that Romero turned down an offer for a nine-month suspension. It never ended up getting to arbitration, though, as the two parties agreed to a six-month ban. Romero's ineligibility began Jan. 12, 2016, so he'll be eligible to fight again in June.

In a statement given Monday to MMA Fighting, Romero said he would be pursuing legal action against the supplement company, which has not yet been named.

"I would like to thank my family, friends, teammates and fans for sticking by me through this ordeal," Romero wrote in a statement. "With that said, yesterday I agreed to a sanction of 6 months suspension for taking a supplement 5 days after my last win that USADA has confirmed was indeed tainted. My management team and I will be pursuing legal action against the supplement company within the next few weeks. For those of you that believed me, I thank you. For the ones that didn't, I hope I have given you a reason to believe in hard work. As for the ones that tried to ruin my name, we will meet very soon. #ynuevo"

Romero defeated Ronaldo Souza at UFC 194 in December and was in line for a middleweight title shot before the failed drug test. The sample was collected in the days after the fight, so it was not an in-competition test.