James Vaughan is expected to be sidelined for 'months rather than weeks' after dislocating his shoulder in Wednesday's friendly encounter with Preston.
The 19-year-old striker suffered the injury less than 15 minutes into the contest after an innocuous collision with Youl Mawene.
He received extensive treatment on the pitch before being stretchered off and taken to hospital.
He will miss Everton's pre-season tour of the United States and the start of the Premiership season because of the injury.
Assistant boss Alan Irvine told evertonfc.com: "It will be months rather than weeks with James - a couple of months I should expect. We will learn the full extent of it tomorrow.
EVERTON boss David Moyes is ready to bid for Manchester United's Alan Smith - after reeling from the loss of starlet James Vaughan for three months.
Moyes has had Smith on his wish-list for weeks and chairman Bill Kenwright has already spoken to United about a deal for the England squad man within their budget.
But now Vaughan's cruel shoulder dislocation has made the Smith move a priority - and talks will begin to agree a fee and see if the player wants to go to Goodison.
AdvertisementUnited will look for around £8m for Smith, with boss Sir Alex Ferguson bullish about the price of his players after selling Kieran Richardson to Sunderland for £5.5m. Moyes could offload James Beattie to part-fund the Smith move.
Everton have been forced into an embarrassing climbdown after their website claimed they had agreed a deal for Juan Roman Riquelme.
A story appeared on the website on Monday morning claiming that the Argentine was on his way from Villarreal.
The 'news' quickly spread on Everton forums, where rumours of a swoop for Riquelme have been fostered over the past month despite the former Barcelona player being on the verge of a move to Atletico Madrid.
The story was quickly removed from the Everton website, where a statement appeared claiming the article was 'completely untrue and appeared as a result of a technical error that occurred during some maintenance work on the site'.
A club spokesperson explained: "During the process of uploading the new home page designs for the website some test data was displayed for a very short period of time and was immediately removed after it had been identified.
"Example data had been used during the testing process and this was unfortunately missed by our appointed web development company during the final upload.
"We have since spoken to our suppliers to convey our complete dissatisfaction at the way in which this mis-information appeared and they have apologized to the Club and any Everton supporters who may have may have read the test article."