Conor McGregor’s UFC 329 injury sparks Sean Strickland’s steroid theory

Conor McGregor's knee injury at UFC 329 has sparked renewed discussion about the circumstances surrounding his return, with UFC middleweight champion Sean Strickland offering a provocative theory about what may have caused the damage.

McGregor's comeback fight against Max Holloway lasted just over a minute before his right knee buckled on his opening kick, leading to a stoppage loss. While Strickland stopped short of making a definitive claim, he suggested the injury could be connected to long-term steroid use, citing his own observations of athletes in similar situations.

"I'm not saying this is it... but every homie I have that has done steroids for too long their bodies become so fragile," Strickland wrote on social media. "I'm not saying that's why but... it does weaken everything."

Strickland expanded on his theory by suggesting that if McGregor had been injured before the fight, he would have been more cautious. Instead, the fact that McGregor threw the kick without hesitation suggests the damage was entirely acute. "If you're injured you're protecting your injury to make it through the fight," Strickland noted. "No. He wouldn't have sent a kick like that if he was hurt. I know from experience."

McGregor has been the UFC's most heavily tested fighter in 2026, though his testing history has been complicated. He was removed from the UFC's testing pool during his injury recovery from the 2021 Poirier trilogy fight, and his drug testing protocol faced issues during his anticipated 2023-24 return. Those testing disputes reportedly contributed to the UFC's 2024 split with longtime anti-doping partner USADA.