Cris Cyborg (left) faced several disadvantages against Ketlen Vieira at PFL Tampa. | 📷: PFL MMA
Nearly two months after her 30th mixed martial arts victory, Cris Cyborg considers the circumstances surrounding her Aug. 22 bout with fellow Brazilian Ketlen Vieira in Tampa, Fla., to be "extremely unusual."
Vieira missed weight by more than seven pounds, turning the final fight of Cyborg’s Professional Fighters League contract into a non-title contest.
Those circumstances now include a positive test for a steroidal substance banned by the World Anti-Doping Agency, according to Mike Mazzulli, director of the Mohegan Tribe Department of Athletic Regulation.
Ketlen Vieira missed weight by more than seven pounds before Cris Cyborg bout; regulator confirms banned steroidal substance in A and B samples
Mazzulli told Sherdog.com that analysis of Vieira’s A and B samples from her in-competition collection returned the same adverse analytical finding.
Mazzulli declined to identify the banned substance but said Vieira received a six-month suspension retroactive to the date of the fight.
"Thank you to Mike Mazzulli and everyone involved in maintaining a serious testing program," Cyborg said. "I believe clean sport deserves strong enforcement."
Vieira was notified of the positive test and provisionally suspended pending the results of her requested "B" sample analysis.
The Mohegan Tribe Department of Athletic Regulation replaced the United States Anti-Doping Agency as the Professional Fighters League’s anti-doping partner in 2025. It previously oversaw Bellator MMA’s drug-testing program.
Representatives for Vieira, the PFL and the Florida Athletic Commission, which regulated the event, did not respond to requests for comment.
The bout was originally scheduled as the first defense of Cyborg’s PFL women’s featherweight title. The 41-year-old, who won the belt by beating Australian Sara Collins late last year, faced a challenger who had spent nearly a decade in the UFC.
Vieira went 10-5 in the Octagon, alternating wins and losses over her final four years with the promotion. Her contract ended after a victory in May, and the UFC opted against re-signing her.
Three months after a decision win over Jacqueline Cavalcanti in her final UFC appearance, Vieira was set to challenge Cyborg for the PFL belt in Florida.
But Vieira missed weight, and Cyborg, who made championship weight, salvaged the main event by agreeing to a non-title contest at 153 pounds.
"I still accepted the fight and stepped into the cage knowing I would be giving up a significant physical advantage," Cyborg said.
Vieira told MMAFighting.com that severe kidney and stomach pain before weigh-ins prevented her from reaching the featherweight limit.
"Ketlen, I respect you," Cyborg said. "I know what it takes to step into that cage. I wish you nothing but success moving forward.
"I know fighters can face difficult circumstances during a fight camp. I have no interest in attacking her personally."
After five rounds against an opponent she described as noticeably strong, the Strikeforce, Invicta, Ultimate Fighting Championship, Bellator and PFL champion was proud of her performance — enough to reconsider retirement.
Unbeaten for nearly eight years since losing the UFC featherweight title to Amanda Nunes, Cyborg intends to fight twice more in MMA and once in boxing.
The PFL currently retains the right to match any contract Cyborg signs. When that period expires, she can negotiate as an unrestricted free agent.
"My career has not been perfect, and I never tried to hide from my past," Cyborg said. "In 2011, I had a positive test for a banned substance, served my suspension, accepted responsibility for what was in my body, and made major changes to the way I managed my team and supplements. Since then, I have competed under the most rigorous testing programs in MMA, including testing overseen by Mike Mazzulli and I have continued to pass those tests.
"That is why I believe strict, independent testing is important. It protects the fighters, the sport and the legacy we work our entire lives to build."