Sunderland target Salvador Cabanas has been shot in the head in a Mexico City bar.
The Paraguay striker, 29, was expected to join Steve Bruce's side this week in a £5million move.
But he is now in a critical condition in intensive care following surgery to remove a bullet from his skull.
Police are unsure whether he was shot as part of a robbery or as a result of an argument that led to him being shot in the bar's toilet.
The forward, who plays for the Mexican team Club America had gone there with his wife Maria Alfonso Mena when the shooting happened.
Two men have been detained in relation to the incident.
The news is a blow for Bruce as he was keen to land the frontman ahead of this summer's World Cup finals.
Cabanas, who has 44 international caps, is a big star in the Mexican League after netting 125 goals in 218 games and was expected to shine in South Africa.
Juan Angel Napout, the president of the Paraguayan Football Association, said: 'We hope that his situation will improve.
'It's hard to express what we feel right now. We must remain calm and pray that Salvador survives.'
Emergency: Cabanas was taken to the Angeles hospital
Crime scene: The bar where Cabanas was shot
Mexico City attorney general MiguelAngel Mancera told TV station Televisa: 'We don't clearly know themotive behind the injury. According to an initial report it was a shotfrom a firearm with a frontal entry point and without exit.
'The player is conscious but he has a heart problem which they're trying to stabilise.
'We're waiting to see what those arrested have to say. It seems that the attack happened in the bathroom of the bar.'
Cabanas has established himself as one ofthe hottest properties in the Americas and leads his country's forwardline alongside Manchester City's Roque Santa Cruz.
He was topscorer in the 2007 and 2008 Copa Libertadores - South America'sequivalent of the Champions League - and was Paraguay's Footballer ofthe Year and South American Footballer of the Year in 2007.
Vigil: Well-wishers gather outside the Mexico City hospital
Club America president Michel Bauer believes the attack to have been unprovoked.
'He arrived conscious and responded well to the questions they asked him as he was going into hospital,' Bauer told Televisa.
'It's a key point that can be encouraging, but until further notice we cannot speculate on anything at all.
'They wanted to assault him. I can confirm that that is what his wife has said, that it was an assault.
'There was no shoot-out nor any quarrel.'
Bruce recently looked at him after a move for Schalke's Kevin Kuranyi broke down.
'I've monitored Cabanas,' said Bruce earlier this month. 'He's a fantastic player and whether a deal is possible for him, I don't know.
'He's somebody who would be of interest to us, but I'm sure if he became available, there would be a lot more clubs interested too.'
Meanwhile, Sunderland have been forced to shelve a bid for Wigan keeper Chris Kirkland after he damaged his collarbone in training. Bruce wanted to raid his former club for the £5m-rated shot-stopper.
He may now switch his attention to Coventry's Keiren Westwood. Kirkland, 28, was his first choice but the keeper is expected to be out for up to three weeks as a result of a collision in training.
The injury is the latest in a long line for the unlucky star, who has a chronic back problem.
Wigan boss Roberto Martinez said: 'This is a completely new injury, I must stress that, and it could have happened to anyone.
'I'm disappointed to lose him but the diagnosis is much better than it could have been and Chris should be back in full training within a fortnight - hopefully.
'It's important we get him back as soon as possible, but we have to be certain the injury is healed before risking him.'
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