"Indiana just gave him away," Durant said on "The Bill Simmons Podcast."
"And I ain't think OKC would even think about giving up anything to trade for him. I didn't think they would do it, but that was a ballsy move."
Durant's approval of the move is rooted in his admiration for George, whom he's played both with (on Team USA) and against.
"I'm looking at only small forwards (as rivals), so that's why I've got so much respect, and I think Paul George is so good," the Golden State Warriors superstar said. "A lot of people disrespect him. Because I play against him and I respect my position."
Pacers president Kevin Pritchard admitted it was difficult trading away the team's best player, but said it was necessary after George informed the club he wouldn't return following the 2017-18 season.
The 27-year-old averaged a career-high 23.7 points last season to go along with 6.6 rebounds, 3.3 assists, and 1.6 steals for the Pacers, who finished seventh in the East and were swept by the Cleveland Cavaliers in the opening round of the playoffs.
PG-13 will earn $19.5 million in the upcoming campaign, and then opt out of his deal to become an unrestricted free agent. The California native, who's known to prefer the Los Angeles Lakers, recently said he'll do his best with the Thunder this year and "see what happens after" when he hits the open market.