Hamilton will leave Mercedes for Ferrari after his bombshell move was announced last week, marking an end to his long-term association with Mercedes.
Hamilton drove for McLaren in his first handful of seasons, powered by Mercedes, before joining their works team in 2013.
While he was criticised for the move at the time, it proved to be inspired as Hamilton went on to win six of his seven world championships at Brackley.
Four of them were alongside Bottas, with the pair remaining unbeaten in the F1 constructors’ championship.
Speaking at the launch of the new Sauber C44 on Monday, Bottas told select media including Crash.net that he never thought Hamilton would move to Ferrari.
“I never thought it would happen,” he said. “I thought in my mind he would stay at Mercedes, but that's Formula 1. Things happen, and I think that it's good for him because he's obviously made the decision and it's a fresh, new start.
“It's a big move in F1, which is going to create some movement as well on the drivers' market for sure.”
Bottas believes it will only take a few races before Hamilton is up to speed in his new team next year.
“I think he will. He's got so much experience of the sport. He's dealt with many different people in the sport, I think there's no problem on that,” Bottas said.
“I'm sure it's going to be quite an exciting project for him to try and get to the top together with Ferrari.
“If anyone can do it, he can do it. ... I think after a few races already he'll be well settled in and then straight on from there."