Conor McGregor's impending return to the UFC lightweight division is already making waves, as one contender has drawn the ire of the former champion.

Justin Gaethje, who is coming off a majority-decision victory over Rafael Fiziev this month at UFC 286, recently declared that he would "probably" quit MMA if McGregor were to jump the line for a title shot.

The Irishman, who is expected to take on Michael Chandler in his return fight, took to social media and fired back at Gaethje in a now-deleted tweet:

"This braindead fool got a title shot off of one single win and it was vs chandler. Yet he will quit and retire if I get the same thing. Classic gathje bird brain. #Jackass Two Title attempt. No wins. #geathje"

McGregor and Chandler are coaching opposite one another in the upcoming 31st season of The Ultimate Fighter reality competition series. The two of them may fight later this year, with the winner maybe in line to face lightweight champion Islam Makhachev.

However, Gaethje has a point in questioning the validity of McGregor's status as a contender. The 34-year-old has fought just four times in MMA since he claimed the 155-pound title in 2016, and he is 1-3 in those fights. He is coming off a broken tibia that kept him out of the Octagon for the entirety of 2022.

Gaethje is 2-2 in his last four fights, with both losses coming in championship bouts. His exciting style makes him a perennial contender, and he expressed interest in a rematch against fellow top contender Dustin Poirier to help clear the logjam at the top of the division.

Perhaps Gaethje will now turn his attention to McGregor, and the two of them could start building a rivalry that would culminate with a clash in the Octagon down the line.