Rooney, who will play for England in a farewell appearance on Thursday night, says he wishes he could have finished his career at Old Trafford.
Speaking to Manchester United's website, Rooney said: “Of course you miss it. It was the highlight of my career, playing for Man United and I was there for so long. But it was the right time.
“I wasn't playing, first of all. I have always been a player who wants to play.
“Obviously I spoke to the manager and it didn't look like I was going to play, so it was the right decision and the right time for me to go.
“Obviously, you wish, the ideal situation was staying there and finishing your career there, but football changes. Different things happen and things happen for a reason.
“I left with great memories. I had a new opportunity to go and play in the States.
“I had a great time at United, though, and again I am looking forward to going back and seeing a few of my team-mates, and a few friends from the staff who I have made along the way."