The South Korean star retired from international football after the 2011 Asian Cup and only has one more year left on his current deal with Sir Alex Ferguson's side.
There were reports last month that Park is likely to sign an extension with United when he returns to the club for their pre-season tour of the United States in August, but the 30-year-old has also been linked with Spanish duo Sevilla and Atletico Madrid.
However, Park told reporters ahead of his charity match in Vietnam he was open to the idea of moving to another club before retirement.
"I won't be able to show my best after one or two years. I don't know how long I can stay at Manchester," said Park.
"I never thought about retirement but it's obvious that I don't have much time left as a player.”
He added: "According to circumstances, I might leave Manchester United and retire in another team.”