The England midfielder received a knock on Friday when preparing for his side's Barclays Premier League opener at Leicester City.
Barkley will undergo a scan in the next couple of days to assess the damage. He was a key player for manager Roberto Martinez last season and earned a place at the World Cup on the back of his club performances.
However, the 20-year-old could be facing several weeks out and that would be a significant blow. It has been reported he could miss between six and eight weeks, and Everton's opening seven fixtures of the season.
Barkley made 34 league appearances last season, scoring six goals, with his performances earning rave reviews and speculation that he might move on. That was quashed, however, when he signed a new long-term deal earlier this summer.