Erik ten Hag expects Casemiro, Lisandro Martinez and Mason Mount to return for Manchester United next month and revealed Victor Lindelof has undergone surgery.
The injury-hit Red Devils face West Ham at the London Stadium on Saturday after securing a dogged, hard-fought 0-0 draw at Liverpool last week.
United have a number of doubts before the match but Ten Hag said their injury problems would ease over the coming weeks.
"We have some illnesses during the week so we have to see who is always available for tomorrow," the Dutchman said on Friday. "Hopefully they are recovered but we have to see.
"(Casemiro and Martinez) are not available before Christmas, so that will be mid-January we expect them back.
"Mason Mount similar, into January. Harry Maguire I expect him early on and Victor Lindelof is not available. He has had surgery so he will be out for a couple of weeks."
Anthony Martial missed the trip to Anfield through illness and Christian Eriksen this week returned to training after a knee injury.
Bruno Fernandes returns from suspension, but Diogo Dalot is suspended following his red card for a pair of quickfire bookings at Anfield.
Amad Diallo and Tyrell Malacia have yet to feature this season, while Jadon Sancho is banished from the first team after falling out with Ten Hag.
Asked about the potential of strengthening the squad in January, Ten Hag said: "The current squad I'm happy (with).
"As we get our players back, I'm sure we have a good squad.
"I think a lot of the way it went in the first (part of the) season, the reasons behind (it are) because many players were not available.
"I'm sure when all the players are available on board -- it looks like, as I said, Casemiro will be back, Martinez will be back, Mason Mount will be back -- we will be much stronger after the winter."
United are seventh in the Premier League table after just one win in their past four games and have scored just 18 goals in 17 league games this season.
