Dominic Calvert-Lewin could miss Everton's Premier League opener against Chelsea after suffering an injury in training.
The 25-year-old, who missed large chunks of last season, picked up a knock during Tuesday's session at Finch Farm.
Everton's medical team are working to understand the extend of the injury and are assessing the England international to see if there is any chance he can play on Saturday.
Doubts over whether Calvert-Lewin can play will be a concern to Toffees manager Frank Lampard.