The Merseyside outfit are unsure on the severity of the 20-year-old's injury and Roberto Martinez has admitted the England international could be out for up to five months
The 20-year-old sustained medial ligament damage in training on Friday as Everton finalized preparations for its Premier League opener at Leicester City on Saturday.
Club manager Roberto Martinez said he expects the 20-year-old to be sidelined for a long period, though a statement published on the club's official website did not put a time-frame on his return.
“We know there is a partial tear of the ligament and that could mean anything from seven weeks to four or five months, so we need to be cautious” Martinez told evertonfc.com.
The club website added that Barkley is undergoing a scan to determine the severity of the injury.After Saturday's 2-2 draw at Leicester, Martinez said: "Ross has been through periods of adversity before and he will know how to cope with this injury."