Sunderland boss Steve Bruce claims "parasites" turned Asamoah Gyan's head with talk of joining one of European football's biggest clubs.
The 25-year-old striker was the subject of repeated speculation throughout the summer with rumours of a move to Turkey emerging as the deadline approached. Bruce is convinced the striker has not recovered from the response to his impressive display for Ghana in their 1-1 friendly draw with England at Wembley in March and the publicity that sparked.
"Since that game at Wembley, all the parasites, as I call them, hover around," said Bruce.
"People are in his ear constantly trying to engineer a deal for him. Certainly since the England game, when he played at Wembley so well on the night, something has been troubling him.
"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, shall we say, and it affects him in the end.
"He was going from Real Madrid to Bayern Munich to Valencia to Atletico Madrid.
"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'."
Gyan has yet to score for Sunderland this season - indeed, the Black Cats have managed only one goal in their four games to date - and he will not end his drought this weekend after being ruled out of Saturday's Barclays Premier League clash with Chelsea at the Stadium of Light with a hamstring injury suffered on international duty.