WANDERERS could head into the derby with Manchester United without a specialist right back after Gretar Steinsson was struck down by illness.

The Iceland international has failed to train this week after picking up a sickness bug and will be monitored over the next 24 hours to see if he stands any chance of playing at Old Trafford.

As Sam Ricketts is out for the season, it could mean that Paul Robinson is again asked to play on the opposite side of the defence, with either Marcos Alonso, or the fit-again Jlloyd Samuel drafted in on the left.

Owen Coyle said he would wait until the last minute before making his choice.

“Gretar has been unwell the last couple of days,” he said. “It’s a bug. He hasn’t trained but I am hoping he will be okay. We will have to wait and see.”

Coyle also revealed that midfielder Mark Davies sustained an ankle injury after an impressive performance off the bench in last weekend's 3-2 FA Cup quarter-final victory over Birmingham City.

“I’d be very surprised if Mark was anywhere near making the 18,” the manager added.

United also have major injury problems at the back, with Sir Alex Ferguson admitting yesterday he was down to only four fit defenders.

Rio Ferdinand could now miss the rest of the season with a calf injury, while John O’Shea and Nemanja Vidic are also out of action.

Coyle offered little sympathy for the Reds’ plight, given his own lack of numbers at the back.

“If they have injuries – so does everyone else,” he said. “We have Sam Ricketts, Zat Knight and the longer terms lads. That happens at football clubs.

“Whether we can take advantage of top players being missing, then who knows?

“Whoever steps in will be an outstanding player. With Vidic and Ferdinand injured, they bring in Smalling, who they have just bought for £10million. That tells you all you need to know.”