"KD broke the league," Garrett said in an interview on WKRK-92.3 in Cleveland on Thursday.
Garrett said that Durant "took the easy way out" by joining a Warriors team that had gone 73-9 the previous season. LeBron James' joining the Miami Heat with Dwyane Wade and Chris Bosh was different because their success was not guaranteed and the Heat "had to jell," Garrett said.
"With KD, you just stick him in and he scores," Garrett said. "You already knew what they had. They were 73-9 before and you put the second-best player in the world on an already all-time great team, and of course you're going to have success, pretty easy success. Anyone can have an off night and they can still find a way to win."
Durant can be a free agent this summer and has said he will stay in Golden State.
"If I were him I would've never made a move like that in the first place," Garrett said. "Me, I'm too competitive to try and ride on somebody's coat tails to get a W. But for him, you might as well stay at the spot you're at now. There's no point in leaving since you've already taken that moniker where he's been called the snake and cupcake and all that.
"You might as well stay and just keep on winning."