Source: Team_Talk
Villa await Petrov scan results
But Villa boss Martin O'Neill conceded that the Bulgaria international has to be "a doubt" for the opening Premier League game with Wigan on August 15.
Petrov suffered the setback during the first half of the Peace Cup clash with Atlante in Spain on Wednesday night.
O'Neill will be desperate for the club's player of the year to be fit, given the departure of Gareth Barry to Manchester City and his failure to bring in new signings to bolster a small squad.
The former Celtic boss said: "It's a concern to us. It's pretty obvious at this moment that he may be a doubt (for the start of the season).
"Roddy MacDonald (the club doctor) put the shoulder back in immediately.
"At this stage we just don't know about the length of time he will be out. We cannot tell just how much damage he has done.
"We'll see how the injury is in the next couple of days."
As one of the club's most experienced and established players, Petrov is a prime candidate to replace Barry as captain.
Right-back Luke Young has already returned home to have treatment on an ongoing thigh problem while left-back Wilfred Bouma is still not ready to return after a year absence with a dislocated ankle.
