Wayne Rooney
Rooney\'s shoulder injury keeps him out of pre-season action once again.

Wayne Rooney's Manchester United future is shrouded in further doubt after the England striker withdrew from the club's pre-season friendly against AIK Fotboll on Tuesday with a mystery shoulder injury.

The 27 year old picked up the problem during the behind-closed-doors friendly win against Real Betis on Saturday, Rooney's first appearance for United this summer after a hamstring problem forced him out of the club's Far East tour.

Amid reports Rooney is ready to hand in a transfer request at Old Trafford this week after the Premier League champions rejected a second bid from Chelsea, news of the injury comes on the eve of his long-awaited first-team return.

"Wayne hurt his shoulder in a fall during a match on Saturday," manager David Moyes said. "It's not too serious and I don't expect it to keep him out for too long.

"I'm disappointed he's missing the game because we were keen to get him back involved and ready to play."

The mystery surrounding Rooney's latest injury problem, which was not reported directly following the 3-0 win over Betis over the weekend at United's Carrington training ground, suggests the injury may be masking last ditch talks between the club and player.

Rooney has not travelled to Stockholm and questions remain over whether he will be available to face Sevilla in Rio Ferdinand's testimonial on 9 August or Wigan Athletic in the Community Shield this weekend - the new season's traditional curtain raiser.

Since Sir Alex Ferguson revealed last season that Rooney had submitted a transfer request the ex-Evertonian has not featured in any official United games, missing the final game of the campaign against West Bromwich Albion to attend the birth of his second child before his pre-season hamstring strain.

Moyes, who gave Rooney his professional debut during the pair's spell at Goodison Park, remains adamant he will not be sold but even amid constant injury problems the striker has been conspicuous by his absence during the summer months.

Furthermore, Rooney - who is still to publically declare his intensions - could be held back from playing for United due to the expected supporter backlash towards him following reports regarding his desire to join Chelsea.

Reports first emerged regarding Rooney's unhappiness with life at United after he was omitted from the team which faced Real Madrid in the Champions League last 16 second leg in March, a tie Ferguson's side eventually went on to lose.