Arouna Kone could be set to miss the rest of the season after scans revealed that the damage to cartilage in his knee is worse than first thought.
He hasn't made an appearance for Everton since sustaining the injury on October 19 against Hull, where they went on to win 2-1.
Coming on as a substitute just after the hour mark, he missed a good opportunity to add his first goal for the Merseyside club.
The Ivory Coast striker signed from Wigan in the summer for £6 million as he made the switch to Merseyside along with manager Roberto Martinez and despite Everton's superb start to the season, Kone is yet to find the net for his new side.
Despite this, it is not ideal this early in the season to be missing a crucial squad player, as his impact from the bench this season has been strong, stretching defences late in games when fatigue is setting in.
Martinez told Everton TV: "We had disappointing news [that Kone] will need a bit of a period away.
"He had a loosened body, a bit of cartilage in his knee, so we need to repair that which will take time."
Ominously Martinez finished his interview adding: "It's going to be a long spell out and that's disappointing."
It isn't all bad news for 'The Toffees' as Darron Gibson's recovery from injury is on track and talisman Romelu Lukaku will be fit for this weekend's fixture against Crystal Palace, despite picking up a knock against Tottenham on Saturday.
Everton will go into this weekend's game as strong favourites following their sublime start to the campaign under Martinez, a polar opposite to the woeful return to Premier League life that Crystal Palace have displayed.
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