McGregor had been training for a rematch against Nate. He lost to Diaz in March, ending a 15-fight winning streak in which he surprised many fans by fighting 25 pounds above his usual weight of 145 pounds, where he holds a title belt. The rematch was set to be fought at 170 pounds.
McGregor stirred fans in April with a tweet saying he had decided to retire young. That prompted UFC President Dana White to respond by saying McGregor had been pulled from UFC 200 because of the dispute over promotional appearances for the card. White said McGregor was refusing to travel to Las Vegas for promotions; McGregor posted on Facebook that he couldn't afford the time he would need to leave his training camp in Iceland.
His later retirement tweet riled up fans, though his threat was never taken seriously.
"It blew up. I was kind of having fun with that to start, it was kind of halfhearted," he said.
"Then all of a sudden it's, 'You're off 200.' It was fun to see it all blow up like that. It was amusing for a while."
McGregor said he some flickering thoughts that he should have participated in the news conferences.
"Seeing the press conferences take place, I was like, I should've just jumped on the (darn) flight. I should've just stuck it out and went with it," he said.
"But sometimes you've got to do what's right for you, and not do what's right for everybody else, and especially if you've done what's right for everybody else a million times over, you should have the right to be able to do what's right for you sometimes. That's what I felt."
McGregor said he remained "committed to the fight game" and met with UFC officials last week in California to smooth out the relationship.
McGregor and Diaz could possibly have a rematch at UFC 202 in August.McGregor even teased an improbable fight against retired boxing great Floyd Mayweather.
"Who doesn't want to conquer both worlds? He's getting old now," McGregor said. "He needs me, I don't need him. Who else can he fight?"
His loss to Diaz punctured the intimidating aura earned by McGregor, the loquacious Irish star who sits alongside Ronda Rousey as the UFC's biggest pay-per-view stars. McGregor had stopped his previous five opponents, and he landed numerous big shots on Diaz before tiring and losing the fight on the ground to Diaz's superior jiu-jitsu.