London - Everton and England defender John Stones will be out of action for 10-14 weeks due to an ankle injury, the English Premiership club said on Thursday.
The 20-year-old suffered ligament damage during Sunday's 2-1 league defeat at Manchester United.
"John will need surgery, which will give us a perfect recovery for his left ankle," manager Roberto Martinez told the club's website www.evertonfc.com.
"We expect him to be out for probably the next 10 to 14 weeks depending on how everything goes.
"It's a clear injury - not a complicated injury. Obviously, it's a little bit of a setback because you don't want to lose any players, but in John's case we were very worried in the moment that it happened because those injuries can become a little bit difficult to treat.
"But this one is going to be straightforward and we are already counting down the days for him to come back and we'll make sure he comes back stronger and ready for the final and most important part of the season."
Stones, 20, has had an impressive start to the season for club and country having just missed out on the final England squad for this year's World Cup.
Able to play at fullback or in central defence, Stone had to withdraw from the England squad for their Euro 2020 qualifiers against San Marino and Estonia.