JULIO ARCA'S left wing sidekick at Sunderland has challenged anyone interested in filling the void vacated by the South American to 'prove their worth'.

Skipper George McCartney has forged a great understanding with the skilful Argentine over the past few months down the flank.

Sunderland are worried Arca will be missing for a vital run of three home games in six days, starting with tonight's match with Preston at the Stadium of Light.

But manager Mick McCarthy may have the 23-year-old back sooner than expected, after a scan revealed damage to knee ligaments picked up in the FA Cup success over Sheffield United on Sunday isn't as bad as first feared.

Arca admitted: "I don't think I will be fit for the Preston game but maybe there is a chance for West Ham.

"I want to be back for that one.

"But because there are so many games coming up it would be stupid to rush back and make it worse so I'll just have to wait and see.

"The main thing is that it's not serious."

Both Sean Thornton and Paul Thirlwell are battling to be the man to play against North End and McCartney wants them to make sure Arca is not missed too much.

"Julio has been a big part of our season and he has scored some important goals," said the Northern Ireland international.

"There's no doubting that Julio has been one of our best players since he has been in the team.

"He will be a big miss, but I'm sure that whoever comes in and plays will be more than capable of doing a good job for the team.

"That is what we need them to do."

McCartney has also backed boss McCarthy's calls for the Sunderland squad to forget about their FA Cup semi-final date on April 4 and focus on their promotion goal.

But the 22-year-old admits that the prospect of playing in the UEFA Cup next season - should the Black Cats reach the final - is one that is hard to believe.

"I don't think anyone would have thought at the start of the season that we would be in an FA Cup semi-final with every chance of reaching the final," said McCartney.

"It's an incredible thing to even consider. It's unbelievable to think we are quite close to playing in Europe.

"We have a young squad here and it would be a great achievement by all the lads if we were to reach a Cup final.

"It would be wrong to say it would mean very little if we reached the final and not get promoted because it would.

"But we have got plenty of games before then to concentrate on.

"Promotion is the priority and that has to be what we are focused on.