Former featherweight title-holder McGregor has not entered the Octagon since November 2016, when he dominated Eddie Alvarez in New York en route to a second-round knockout that saw him become the first fighter in company history to hold two belts simultaneously.
The Dubliner subsequently made his professional boxing debut in Las Vegas in August 2017, losing to former five-weight world champion Floyd Mayweather Jr via a 10th-round stoppage in one of the most lucrative bouts in history.
While McGregor has said that he is confident of reaching an agreement to return to the UFC before the end of the year with "multiple opponents on the platform", his exact plans have yet to become clear as speculation over a potential rematch with Mayweather under MMA rules continues to circulate.
A potential clash with undefeated 155-pound contender Nurmagomedov in his native Russia - a location that president Dana White has confirmed that the UFC are planning to visit along with Hawaii - has been speculated in addition to a possible meeting with Tony Ferguson or a trilogy fight against Nate Diaz as one option for McGregor's eventual return, though 'The Eagle' evidently doubts that his rival will ever come back.
"When did Conor compete last time in MMA?" he told TMZ Sports. "I forget about this. A long time. He's [a] boxing guy. He's good to stay in boxing because you have to compete in MMA like wrestling, grappling, conditioning, like 25 minutes. It's different. It's very hard to him.
"But when [is he going to come back]? They talk about [the] Mayweather fight. I don't think he's gonna come back."
Ferguson vs Khabib for "real belt"
Ferguson earned the title of interim lightweight champion with his third-round submission of Kevin Lee in October and is due to face Nurmagomedov - who destroyed Edson Barboza last time out - at UFC 223 on 7 April after three previous cancellations including before UFC 209, when the number-two ranked Russian was taken to hospital following weight management issues.
The poster for the event states that it is for the lightweight title and White has previously confirmed that the winner of that contest would be undisputed champion, though the lack of an update with regards to McGregor's situation has only led to more confusion over what exactly will be at stake at Barclays Center in Brooklyn.
For his part, Nurmagomedov is adamant that the fight with Ferguson is for McGregor's belt and that 'The Notorious' will indeed be stripped of his title soon.
"We're going to fight for his belt," he said. "The UFC strip his belt now, we're going to fight for [the] real belt.
"100% [they will strip him]. I have [a] contract, [for the] real belt. What are they gonna do? They have only one real belt. They have [the] interim belt and they have [the] real belt. They send me [the] contract, we're gonna fight with Tony Ferguson for [the] real belt."
Asked if the UFC had yet told McGregor anything about stripping his belt, Nurmagomedov added: "I don't know, maybe they don't want the upset because he makes good money. I don't know about this. I know I'm going to fight for the real belt because I have [a] contract."
If McGregor's title is taken away over the coming weeks, then it could be that his return will be for against the winner of Ferguson-Nurmagomedov for the undisputed title. He is expected to be in attendance at UFC 223 with teammate Artem Lobov fighting on the card against Alex Caceres.
IBTimes UK has contacted the UFC for a response to Nurmagomedov's latest comments.