Aston Villa are sweating over the fitness of their player of the year Stiliyan Petrov, who suffered a dislocated shoulder during the Peace Cup game with Atlante.

The Bulgarian midfielder, a strong candidate to replace Gareth Barry as captain for next season, suffered the setback during the first half of Villa's 3-1 success in Spain.

It is a second blow for O'Neill as right-back Luke Young has flown back to England after suffering a reaction to his ongoing thigh problem.

The Villa squad is already stretched to the limit with the departure of Barry, Martin Laursen, Zat Knight and Stuart Taylor, and only the arrival of Stewart Downing so far this summer.

The midlands club expect to find out in the next 48 hours the extent of Petrov's setback. O'Neill told Aston Villa TV: "Stiliyan dislocated his shoulder and our doctor put it back in immediately.

"He is feeling a little better but we don't know just at this moment how much damage he has done. It was obviously the low point of the night.

"But we don't know the extent of the problem. We will find out over the next couple of days to see how it settles down. We just don't know. But it is a concern to us."

Petrov took time to adapt to life in the English Premier League after becoming O'Neill's first major signing in a £6m switch from Celtic during the summer of 2006. But he sparkled in a holding role last season as Villa clinched a place in Europe for the second successive season.