Reynolds’ exit comes on the back of Will Evans’ departure to Chesterfield earlier the summer.
The pair were excellent for Gary Waddock’s side last season and now the manager needs to find replacements.
Reynolds says his new boss John Still was the main reason he agreed to move to north London.
“It was a very big thing for, his reputation speaks for itself,” he told the club’s website. “He's won the league three times and what more can you say!
“He's the most successful manager in the league, he's experienced and he also used to be a defender which is key for me, I want to learn from him and that definitely had a big influence.”
Reynolds now wants promotion after falling in the play-offs two years running.
He added: "When I was looking at where to go, I was looking at going to a successful team and I want to get promoted, as simple as that. I've come close in the last two years, falling just short.
"I didn't want to just join anyone for the sake of joining them, I want to get promoted and from speaking to the gaffer, that's what he wants to do. It's definitely the main objective, getting promotion back to the EFL for the club and it's supporters.”