Steve Bruce has said that Asamoah Gyan needs to rediscover his focus following the transfer window.
The Sunderland manager feels that the 25-year-old became distracted when he was linked to several major European clubs during the period.
Bruce pinpoints the Ghana player's performance in Ghana's 1-1 draw against England in March as the source of interest in the striker.
"Since that game at Wembley, all the parasites, as I call them, hover around," BBC Sport quotes him as saying.
"It's very difficult, the constant speculation. No matter what you try to quash or quell, and the people around him, the people who want to make a fast buck, and it affects him in the end.
"He was going from Real Madrid to Bayern Munich to Valencia to Atletico Madrid."
Bruce added that he has met with the striker, who has not yet scored this season, to discuss a return to form.
"We have had a discussion with him and he needs now to focus and get himself back on track again and be the Asamoah Gyan we know he is capable of. These things affect these players, and it has affected Asa.
"I had a conversation with him two days ago to say, 'Look, the window as now closed, Asa. Right, we need to see you back playing again and back the way you know you can play'."
Sunderland will face Chelsea at 3pm at the Stadium of Light today.