It’s still unclear why Paulo Costa isn’t fighting Yoel Romero in the main event of UFC’s upcoming card in Florida on April 27, but the Brazilian guarantees he’s not in trouble with the United States Anti-Doping Agency (USADA).

Romero, a former UFC middleweight title challenger, was on Ariel Helwani’s MMA Show on Monday and said that he heard the reason why “Borrachinha” wasn’t fighting him anymore is because he’s under investigation for a possible drug-test failure.

“The problem is, what I can hear, is that Paulo Costa, he have the positive test for the USADA. That’s what happened,” Romero said. “The UFC called my manager and said Paulo Costa is out because he’s positive. Now, we need to see another opponent. They say, ‘We have ‘Jacare’ Souza,’ I said, ‘OK, I fight him.’”

A middleweight clash between Romero and Costa has been in the works for months. However, when the Cuban athlete was finally eliminated from a reality TV show, the UFC booked him in a five-round rematch with Ronaldo Souza instead of Costa.

MMA Fighting reached out to Costa on Monday and asked about Romero’s comments. The undefeated Brazilian wouldn’t explain why he’s no longer fighting on April 27, but said that Romero’s doping allegations are “not true.”

Costa's manager, Wallid Ismail told MMA Fighting that Romero is lying, that "there was no failed doping test."

“It’s not true, there was no doping, he wasn’t caught doing [anything],” Ismail said. “That’s a lie. A big lie.”

According to Helwani, Romero later clarified he “had only heard that Paulo Costa failed a USADA drug test but he is not sure if that is accurate at this time.”