After spending the first 10 seasons of his career with the Washington Capitals, Green signed a three-year, $18 million contract with Detroit on July 1.
He will face his former team for the first time Tuesday when the Red Wings play the Capitals at Joe Louis Arena (7:30 p.m., TVAS, FS-D, CSN+).
"I was there a long time and obviously, sometimes change is good. I felt I was becoming a little bit stagnant there, so I wanted to evolve," Green said Monday. "And I felt that coming here would be the best thing for that. It was difficult, a lot of friendships there. Obviously there will be friends on the ice [Tuesday].
"It'll be strange, but I've moved forward now. I think it's more exciting than anything. I know the personality in the dressing room and how most of these guys play, so it will be fun. But it will be fun because we're competing."