Everton defender Phil Jagielka has undergone a second knee operation and may not play again until after Christmas.
Jagielka, 27, has been sidelined since damaging knee ligaments in April but had been hoping to return to action before the end of November, but a problem - described by Everton as 'a small cartilage tear' - means the England international's comeback will be delayed.
Moyes said: "Jagielka had an operation on a tear in his meniscus, which is the cartilage in his knee. We think [it has set him back] four to six weeks. He was down initially but he's on the road to recovery now."
Moyes told club's official website that striker Victor Anichebe has also suffered a complication in his recovery from a knee injury.
Anichebe has not played since February and the 21-year-old appears some way off a return to the first team.
Moyes said: "Victor's not in a good way either. He had the pin taken out four to six weeks ago which had been catching on the side of his knee.
"Now what has happened (is that) he has a massive growth of bone and has a really big knee at the moment. We don't know how long it will be."
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