Veteran heavyweight Josh Barnett is in the process of finalizing a mutual release with the UFC.
Barnett, 40, confirmed his pending release in a statement to ESPN on Wednesday. MMAJunkie reported earlier that Barnett had secured a release, but he stressed it is not yet finalized.
"It's true that I have asked for my release and we are discussing the terms now," Barnett said. "Zuffa [parent company of the UFC] has been fantastic and above-board since I re-signed with the company [in 2013]. Every promise made has been kept and I have no disparaging words for them."
Barnett (35-8) said his request was based upon a lack of trust in the United States Anti-Doping Agency (USADA), which oversees the UFC's anti-doping program.
In late 2016, Barnett failed an out-of-competition drug test administered by USADA. The agency sought a four-year suspension, despite evidence the result of the test was caused by a legal, contaminated supplement.
Barnett ultimately took the case to an independent arbitrator, and became the first UFC athlete to successfully appeal a USADA sanction through an arbitration process.
That process took 15 months, however, and Barnett said he did not feel comfortable re-entering the UFC's testing pool, which would be required if he ever wanted to fight in the Octagon again.
"After everything I went through with USADA, and my vindication in that case, I don't feel comfortable giving the control necessary to USADA that would continue my career in the UFC," he said.
Barnett is a former UFC heavyweight champion. He fought outside the promotion from 2003 to 2013. He has not fought since a submission win over Andrei Arlovski in September 2016.
The UFC partnered with USADA in 2015, to implement a comprehensive, year-round drug testing program. Immediately following Barnett's arbitration ruling in March, a USADA representative told ESPN the agency followed its normal protocol in that case.