Aston Villa defender Richard Dunne has been forced to withdraw from training with a sore Achilles ahead of Saturday's FA Cup semi-final against Chelsea.
The former Manchester City captain has been troubled by the problem in recent weeks and Villa could ill-afford to be without his experience for the Wembley meeting with Carlo Ancelotti's side.
Martin O'Neill said: "Dunne has had a bit of a setback and he came out of training this morning. Richard was a bit sore. It is an injury we have to be nursing through. It has been troublesome for a while but he definitely will want to play."
Dunne has been the mainstay of a Villa defence that has the fourth best record in the Premier League - behind Manchester United, Tottenham and Saturday's opponents Chelsea.
However, Villa were beaten 7-1 by the Blues in the Premier League last month and Dunne, who joined the club from City in £5 million deal in the summer, will be out for revenge by knocking Chelsea out of the FA Cup.
The good news for Villa is that midfielder James Milner has resumed training after being rested for the game at Bolton Wanderers last week, also with an Achilles problem.