Larsson joined United on a short-term deal during the 2007 January transfer window and made an instant impact at Old Trafford.
United boss Sir Alex Ferguson wanted Larsson to extend his deal, but Larsson decided to return to Sweden at the end of that season.
“If there is one regret I have from my career, it is that I came home to Sweden when Mr Ferguson was trying to get me to stay at Manchester United,” Larsson told www.fifa.com.
“I should have stayed at United for longer because I had a great time there and everyone at the club was very keen to keep me. My time there was too short.
“The whole experience was fantastic and, although I was 35 at the time, I still felt that I had some good football in me. That is a regret.”