"A deal was done with Houston early, then for some reason, whatever happened behind the scenes, it didn't go through," Anthony told SiriusXM Radio. "It fell through, then we had to really start paying attention and thinking about other options."
The Knicks and Rockets discussed a deal with Anthony on and off throughout the summer and were close to completing a trade in July before the Knicks hired general manager Scott Perry, according to sources. The teams struggled to find the third team necessary to complete a trade.
Anthony said he was prepared to rejoin the Knicks to start the 2017-18 season. When the Knicks front office asked him last week if he would add the Thunder to the list of teams he would agree to be traded to, Anthony decided it was time to move on.
"I don't think it would have been beneficial for me to come back to media day after everything that was going on in the offseason," Anthony told SiriusXM. "For me to have to deal with that, it would have been unfair for the organization, the Knicks, to have to deal with that. It would have been too much noise, too many questions to answer, and I don't think either party wanted to deal with that."
Anthony had to waive his no-trade clause to join the Thunder. He also agreed to forgo a trade kicker worth $8.1 million to help facilitate the deal.
The trade united Anthony with reigning NBA MVP Russell Westbrook and offseason acquisition Paul George. It was the second time Anthony thought he would be paired with the former Indiana Pacers star, saying that draft-night deals would have sent both players to the Cavaliers.
"Actually, it was funny because me and PG was supposed to be in Cleveland on draft night," Anthony said. "We were communicating about that. The deal was actually done, and it got called off on draft night, so me and PG stayed connected throughout the course of the [offseason]. We never even talked about OKC, though."
Anthony said he has "close friendships" with Westbrook and George as Oklahoma City's new Big Three prepares to open the regular season by hosting the Knicks on Oct. 19. The 10-time All Star added that he's reinvigorated by a change in scenery.
"My motivation is just different now. I kind of lost that motivation a little bit in New York. But I was still able to go out there and play and get through it," Anthony said. "... From an individual standpoint I feel born again, feel rebirth, a different type of energy within myself, around the guys, around the organization, around the city. You can feel it."
ESPN's Ian Begley contributed to this report.