Sunderland duo Jordi Gomez and Wes Brown have been ruled out of the remainder of the club's Premier League survival fight through injury.
Spanish midfielder Gomez suffered a suspected fractured knee-cap in training and will be absent for matches against Leicester City, Arsenal and Chelsea, with Sunderland currently sitting two points above the relegation zone.
Defender Brown is also expected to miss the rest of the campaign with a knee problem, while midfielder Jack Rodwell (hamstring) is not fit to face Leicester on Saturday.
"We have some problems," said Advocaat. "Jordi Gomez, Jack Rodwell and Wes Brown will not be involved.
"John O'Shea is back and so is our Italian friend, Emanuele Giaccherini.
"O'Shea trained on Thursday and Friday but Wes gave so much last weekend that he needs a little break.
"He has some problems with his knee and we don't know exactly how long it will take, but Jordi will be out for at least six weeks so both are probably out for the season.”
