Alex Iwobi left the field in tears after suffering an injury in a tackle with Tyrell Malacia on Friday evening.
The Nigerian midfielder was stretchered off after seeming to injury his ankle in a challenge from the Dutch left-back, handing manager Frank Lampard a hefty injury blow.
The Toffees take on Southampton next after their 3-1 defeat to Manchester United on Friday - which saw banners unfurled calling for the board to be sacked - as the pressure continues to build on Lampard after a string of poor results.