Sunderland defender Michael Turner is facing a lengthy spell on the sidelines after suffering damaged knee ligaments.
The loss of Turner is another major blow to Black Cats boss Steve Bruce, who discovered earlier on Thursday that Titus Bramble is out for up to six weeks.
That will leave the reeling Wearside boss without both of his first-choice central defenders until well into the New Year.
Former Hull City defender Turner sustained his injury when he collided with a post during Monday night's 2-2 Premier League draw with Everton at the Stadium of Light.
The 27-year-old is to undergo a further examination to discover the full extent of the problem, but Bruce is already resigned to being without another key member of his squad for an extended period.
Bruce told the club's official website: "It's horrible news. Michael whacked his knee against the post on Monday and damaged knee ligaments.
"He will see a specialist today. I believe it could be months rather than weeks, and that's a big blow to us.
"I hope the ones who come in can do the job which they've been doing. They'll be a big act to follow."