Park Ji-sung has cast doubt on his future at Manchester United.
The South Korea is expected to be offered new terms by United when he returns to England for preseason.
Park told the Daily Mirror: "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.
"I never thought about retirement but it's obvious that I don't have much time left as a player. According to circumstances, I might leave Manchester United and retire in another team."