Aston Villa boss Martin O'Neill has backed midfielder Stiliyan Petrov to bounce back after "a crisis of confidence".

The Bulgaria international, who has struggled to recapture the sort of form which made him a regular in O'Neill's Celtic side, was left out of the squad for Sunday's win at Reading. And with the midfielder, by his manager's own admission, being forced to play out of position this season, things have not been easy for Petrov.

He now faces further competition with the news last night that Czech international midfielder Patrik Berger has finally recovered from the injury which has kept him sidelined all season.

The 34-year-old former Liverpool star is in contention for a place in the Villa side, which tackles Arsenal at The Emirates Stadium on Saturday.

O'Neill, who substituted Petrov at half-time in the 4-1 victory over Newcastle United three weeks ago, said he wanted to take the 28-year-old "out of the firing line" so that he could recapture his confidence in himself and his ability.

He said: "I've decided to take Stiliyan out of the firing line at this minute to get his confidence back. All too fleetingly, he has shown really great form but, to be fair, we've played him out of position because he likes to go and play off the centre-forward.

"At the moment, he's not involved but he's got a great determination about him. I know him very well and he's very strong mentally. He knows himself he's capable of so much more when his confidence is high.

"His confidence is a bit low at the moment, but he'll bounce back, I've no doubt about it."

O'Neill brought Petrov to Villa Park in his first season in charge and is sure he will still get a return on his investment.

He said: "How long will he be out? He's part of the squad and people are fighting for positions and even though our squad isn't that big, that is great news.

"I think players deep down have a realisation of how they are playing and the best way to get confidence back is to get out there and start going back to basics again.

"They should go out and practise and, to be fair with 'Stan,' he does nothing but that. He gets himself into a mind frame where he wants to be incredibly fit and, at times, there has been a case of over-training. "In his defence, he has had to adjust to a completely new position here he never played this way at Celtic. We had a lot of the ball and he was able to get forward beyond the likes of Henrik Larsson, Chris Sutton and John Hartson.

"Here, he is having to play a much more sitting role, even when he plays on the right-hand side. I think all of these things are factors but, at the end of it all, he has the capability of playing better and I am sure we will see that soon.'

Berger's return, meanwhile, has prompted O'Neill to forecast he will repeat the impressive form he displayed in Villa's great unbeaten run in to the end of last season.

His performances last year earned him another 12-month Villa contract but a series of niggling injuries crept in which have kept him on the sidelines for much of the season.

Berger completed an hour with the reserves in Monday night's 1-1 draw with Reading at Villa Park. O'Neill said: 'I think Patrik has been unfortunate. He's been injured for a fairly lengthy time. His pre-season was going particularly well and then he got injured the day before the Liverpool game on the opening day of the season. Psychologically, that was a big knock-back for him. He had ended the season so brilliantly the year before.

"He has been thwarted by injuries this year, but anybody is capable of coming in because we don't have the numbers and I am delighted to see him back again. If he makes anything like the impact we saw in the final third of last season, that will be good enough.'

Berger is out of contract in the summer and has been linked with Slavia Prague in his native Czech Republic.