Martin O'Neill has warned striker Ji-Dong Won there will be little time for rest when he returns from the Olympics.
Ji, 21, is set to face Brazil on Tuesday in the semi-finals of the Olympic tournament- just days after helping knock Team GB out of the competition.
The South Korean is due to return to Wearside on Monday, with O'Neill making it clear a rest period is unlikely.
"I don't think we can afford to give Ji any time off after the Olympics," O'Neill told the Evening Chronicle. "It is going to be a matter of him coming straight back into training with us.
"I'm hoping that when he comes back from the tournament, he will be ready to go. He did have some time off in the summer between the end of our season and the start of his Olympic preparations with Korea, at least."
O'Neill also hinted that Ji, who started just two games for the club last season, is likely to see more playing time this year having impressed with his Olympic performances.
The Black Cats manager said: "I spoke to his agent when we were out in Korea for the Peace Cup last month and, obviously, he is very keen for him to get more playing time this season and we'll see what develops."