Daniel Agger will have back surgery next week and is likely to be out for six weeks, missing the clash with Aston Villa.

The Liverpool defender has missed the first two Premier League games of the season, having been troubled with the injury all summer.

He adds to boss Rafael Benitez's defensive injury problems.

Martin Skrtel is also a doubt for the visit of Martin O'Neill's side, which means that teenager Daniel Ayala stands by having made his full debut in the 4-0 win over Stoke on Wednesday.

New Greek defender Sotirios Kyrgiakos could also figure once his £2m move has been completed and international clearance acquired.