The 28-year-old Scotland international had an operation in Sweden yesterday after the programme of exercises he had initially been prescribed by specialist Professor Hakan Alfredson failed to pay dividends.

He now faces between four and six months on the sidelines just at the moment when his club could use his experience as they attempt to drag themselves away from the relegation mire.

Manager Steve Bruce told the Black Cats' official website, www.safc.com: "Craig had the operation yesterday and it went well. He will be out for about four to six months now.

"Craig's been following a programme, but when the specialist had a look at the knee again, we were left with no choice but to go ahead with the surgery.

"That just sums our luck up at the moment."

Bruce's dismay is understandable - Gordon's misfortune is the latest to befall Sunderland in a season which has seen the likes of Titus Bramble, Michael Turner, Danny Welbeck, Fraizer Campbell and David Meyler all suffer significant lay-offs with knee injuries.

Indeed, Bramble is unlikely to play again before the end of the current campaign and Campbell may miss the bulk of the next if he requires a second operation to repair the cruciate ligament damage which has kept him out of all but four games this time around.

Gordon has spent the last six games on the bench as back-up to 23-year-old Belgium international Simon Mignolet after returning early from duty with Scotland in February.

Bruce hinted last week that he feared the worst as the former Hearts keeper prepared to head for Scandinavia.

However, after seeing errors from Mignolet contribute to the club's 2-0 Barclays Premier League defeat at Birmingham on Saturday, he suggested that surgery would be put on hold until the end of the season to allow the £9million man to play a role in the quest for the win the manager believes will end their worries.

But once Professor Alfredson was able to examine him, it was immediately apparent that Gordon could not carry on.

Sunderland face crucial home games against Wigan and Fulham in the next fortnight in which they are desperate to end a run of nine league fixtures without a win which has seen them slide from sixth place into 15th.

They head into Saturday's clash with Roberto Martinez's rejuvenated side sitting just five points clear of the relegation zone and in danger of being reeled in by the chasing pack if they cannot turn things around quickly.

Gordon's name has been added to an injury list which at the weekend included Bramble, Campbell, John Mensah, Anton Ferdinand, Kieran Richardson and Sulley Muntari and was extended by the hamstring problem Welbeck sustained at St Andrews.

Despite the lack of bodies, made worse by confirmation of Gordon's lay-off, Nyron Nosworthy will not be returning to Wearside from his loan spell at Sheffield United.

The relegation-threatened npower Championship Blades announced at the weekend that the defender, whose contract expires at the end of the campaign, was going back to his parent club but Sunderland insist that is not the case.