Everton and England defender John Stones may be out for the rest of 2014 after it was confirmed that he needs surgery on an ankle injury.
The 20-year-old damaged ligaments in the 2-1 defeat by Manchester United and is set to miss between 10 and 14 weeks.
Stones was forced to pull out of Roy Hodgson's squad to face San Marino and Estonia in Euro 2016 qualification.
But team-mate Ross Barkley is expected to train again next week, after two months out with a knee ligament injury.
"It's a clear injury, not a complicated injury," Everton boss Roberto Martinez said of Stones.
"It's a little bit of a setback but in John's case we were very worried because those injuries can become a little bit difficult to treat.
|The games Stones may miss|
|Premier League: 18 Oct: Aston Villa (h), 26 Oct: Burnley (a), 1 Nov: Swansea (h), 9 Nov: Sunderland (a), 22 Nov: West Ham (h), 30 Nov: Tottenham (a), 3 Dec: Hull (h), 6 Dec: Manchester City (a), 14 Dec: QPR (h), 20 Dec: Southampton (a), 26 Dec: Stoke (a), 28 Dec: Newcastle (a)|
|Europa League: 22 Oct: Lille (a), 6 Nov: Lille (h), 27 Nov: Wolfsburg (a), 11 Dec: FK Krasnodar (h)|
|England internationals: 9 Oct: San Marino (h), 12 Oct: Estonia (a), 15 Nov: Slovenia (a), 18 Nov: Scotland (a)|
"But this one is going to be straightforward and we are already counting down the days for him to come back for the final and most important part of the season."
If he returns within 10 weeks, Stones is likely to be absent for 16 Everton matches as well as four for England.
He made his international debut in the 3-0 win over Peru on 30 May and has won four caps, starting at right-back in England's 2-0 win over Switzerland in their opening Euro 2016 qualifying match last month.
Meanwhile, midfielder Barkley, 20, is hoping to be back in first-team action for Everton within a fortnight, after recovering from the knee ligament injury he picked up on the eve of the season.
"On Monday we expect Ross, with the green light from the medical department, to join the group," Martinez said.
"Now it's a matter of getting him match fitness and getting him up to speed."