Everton have confirmed that Muhamed Besic did not travel with the squad for their pre-season tour after injuring his ankle.
The midfielder picked up the knock in the Toffees' 4-0 win in a pre-season friendly against Swindon Town at the weekend, just 48 hours before the club departed for the Asia Trophy in Singapore.
Manager Roberto Martinez told the club's website: "It's not nothing too serious, but he hasn't traveled. He'll be working hard back at Finch Farm."
Seventeen-year-old Ryan Ledson takes Besic's place in the squad.