CONOR McGREGOR is yet to enrol into the UFC’s anti-doping pool ahead of his return fight against Michael Chandler.
UFC president Dana White announced the Irishman will face Chandler in his comeback bout, set for September.
But according to TSN Sports, McGregor has not yet signed up to US Anti-Doping Agency tests, required for any competitor in the UFC.
He must be in the pool for a minimum of six months and have at least two negative tests prior to any bout.
McGregor, 34, has been out of action since July 2021, when he broke his leg in the opening round of his trilogy bout with Dustin Poirier, 34.
The ex-UFC champion spent the entire of 2022 rehabilitating the horror injury after surgery the year before.
As a result, McGregor was not signed up to USADA’s random, all-year round testing.
It means he must enrol by April in order to be eligible to fight Chandler, who he is set to coach against on The Ultimate Fighter.
The Ultimate Fighter is a reality series where contenders live, train and fight together to win a UFC contract.
Season finalists then meet in a finale, while coaches McGregor and Chandler, 36, also headline against each other.
McGregor stars on The Ultimate Fighter for the second time, following his 2015 appearance against Urijah Faber, now 43.
And UFC boss White confirmed his return to both the series and the octagon.
He said: “We just confirmed the coaches for season 31 of The Ultimate Fighter.
“Conor McGregor and Michael Chandler will go head-to-head as coaches of The Ultimate Fighter.
“Team McGregor versus Team Chandler. This season premieres Tuesday May 30 and runs through Tuesday August 15 on ESPN and ESPN+.
“Then at the end of the season McGregor and chandler will fight live on ESPN+ PPV and I do not have a date or location for that but we will announce it soon.”