Rountree out of UFC 303 bout vs. Hill after taking banned substance

Khalil Rountree Jr. is out of his fight against former UFC light heavyweight champion Jamahal Hill at UFC 303 on June 29 after he says he accidentally took a banned substance.

Rountree said Saturday in an Instagram post that he's under temporary suspension after reporting the news himself to UFC executives Jeff Novitzky and Donna Marcolini.

"I'm gutted to deliver this news to you all, but I will not be fighting at UFC 303 due to consuming a banned substance," Rountree wrote. "I did not do this intentionally, and I am doing everything I can to get this situation taken care of."

Rountree said he was using a personalized tailored supplement service and accidentally received a supplement that contained dehydroepiandrosterone (DHEA), which is prohibited at all times under the UFC anti-doping policy. Rountree said he took the supplement before realizing DHEA was an ingredient.

"I've provided (the UFC) with all of the information to show that this was not a matter of cheating or to enhance performance," Rountree wrote.

Rountree was set to have the biggest test of his career against Hill in the UFC 303 co-main event at T-Mobile Arena in Las Vegas. Rountree has won five in a row, highlighted by a knockout win over Anthony Smith last December, and had a chance to break into the top five at 205 pounds with a win over the No. 3-ranked Hill.

The UFC is seeking a replacement opponent to face Hill at UFC 303, a promotion official told ESPN's Andreas Hale. The event will be headlined by Conor McGregor's long-awaited return against Michael Chandler.