London - Manchester United midfielder Michael Carrick will be out for four weeks with a ruptured muscle, manager Louis van Gaal said on Friday.
The 33-year-old Englishman will miss the visit of Leicester City in the Premier League on Saturday and could be absent for another six games during February.
Carrick has been a key member in the United side since his return from injury in November, which coincided with six consecutive wins after an indifferent start to the season.
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Despite the absence of the midfielder, who has also filled in at centre back during an injury crisis, Dutchman Van Gaal has no plans to add to his fourth-placed squad during the January transfer window.
The former Netherlands boss said his only business will be to sell players, starting with midfielder and vice-captain Darren Fletcher to West Ham United.
"I read every day that I or United are interested in other players," Van Gaal told a news conference. "We are only selling players, not buying them.
"He (Fletcher) is at West Ham now I believe, so we will have to wait and see.
"He is my third captain so he is an important guy in the dressing room, I like him as a person so we shall miss him. But he hasn't played so many times and that is always the main goal of a player. We have talked about that and he prefers to play."
Van Gaal's side host bottom club Leicester expecting a tough test, with United having suffered a 5-3 defeat after squandering a two-goal lead in the reverse fixture in September.
After a number of drab performances, including a home defeat by third-placed Southampton and a goalless draw at fourth tier Cambridge United in the FA Cup, the United boss will approach the game differently.
"It's true that we have not created too many chances in the last two or three matches, but therefore I have changed system," Van Gaal said.
"We have to play more quickly because our opponents are defending and make a small space, so it's difficult then to attack. Everybody knows that but we also need a little bit of luck and we have to finish the chances."