The UFC released veteran Diego Sanchez on Tuesday, promotion president Dana White confirmed to ESPN's Brett Okamoto on Thursday.
Sanchez was scheduled to meet Donald Cerrone in the UFC Fight Night co-main event on May 8, but that bout is off as a result of his release. It was initially reported Wednesday that Sanchez withdrew for undisclosed reasons.
The 39-year-old teased on Instagram earlier Thursday that he was no longer under contract with the UFC, writing he's "free at last." He tagged several MMA promotions in the post.
The UFC released Sanchez because neither his coach nor his attorney would confirm the fighter isn't suffering from short- or long-term medical issues, according to White.
Sanchez's coach, Joshua Fabia, recently asked the promotion for every medical document it received throughout the fighter's UFC career to process his medicals for the Cerrone bout, White said.
Sanchez's attorney later told UFC chief business officer Hunter Campbell he couldn't ensure Sanchez was in good health because he's not a neurologist, White said. The UFC decided to cancel the Cerrone fight and terminate Sanchez's contract following that comment.
Tension between Sanchez and the UFC seemed to rise during the latter chapter of his Octagon career, especially after he began working with Fabia - who has become a controversial figure in MMA - in 2019.
On Thursday, Sanchez posted two video clips of Fabia confronting the UFC's broadcast team over the fighter's treatment on previous broadcasts. The confrontation happened during the broadcast team's fighter meeting with Sanchez ahead of his bout against Jake Matthews last September.
Sanchez rose to fame after winning "The Ultimate Fighter 1" in 2005 and was the last cast member on the UFC roster. He exits with a 19-13 record in the promotion.
Throughout his 16-year UFC stint, "Nightmare" picked up notable wins over the likes of Nick Diaz, Kenny Florian, Joe Stevenson, Clay Guida, and Takanori Gomi. Sanchez was once known for his brawling style, which led to seven "Fight of the Night" performance bonuses. His bout against Guida was inducted into the UFC Hall of Fame in 2019.
Sanchez challenged BJ Penn for the lightweight title in 2009, but he lost by fifth-round TKO.
Sanchez is coming off a one-sided decision loss to Matthews at UFC 253 and is 1-2 in his past three contests. His most recent victory is a disqualification against Michel Pereira in February 2020.