Manchester - Manchester City manager Pep Guardiola has indicated his main priority in the January transfer window will be to buy a replacement for injured defender Benjamin Mendy.
France left-back Mendy will be out for the next six months after suffering cruciate knee ligament damage during City's victory over Crystal Palace on September 23.
Guardiola can use Fabian Delph, Danilo or Ukrainian youngster Oleksandr Zinchenko in Mendy's absence, but he believes the former Monaco defender, signed for 52 million in the close season, will be missed hugely.
The City manager spoke about Mendy's influence after refusing to comment on the possibility of signing Arsenal's Alexis Sanchez in January.
City failed with an attempt to sign Sanchez in August, but Arsenal manager Arsene Wenger indicated in Thursday that the Chile forward, along with team-mate Mesut Ozil, could be sold when the transfer window reopens because both will be out of contract at the end of the season.
"The transfer window is closed now. Unfortunately it was long open, but now it is closed," Guardiola told reporters on Friday.
"We will see about January, we are in October. The only problem we have - a big, big problem we have - is Mendy, six months out. It's a big problem.
"We'll suffer even though we have the exceptional Fabian, Danilo, and even Zinchenko. Mendy was and is so important for us and unfortunately six months (is) a long time."
Guardiola has indicated that forward Sergio Aguero is ahead of schedule in his recovery from a broken rib sustained in a recent taxi crash.
Aguero returned to light training on Tuesday, even though he looked set to be out for more than a month after being injured in the accident in Amsterdam on September 28.
The crash happened when the striker was on his way to the city's airport to fly back to Manchester after attending Colombian singer Maluma's concert on his day off.
Medical officials within the Argentina set-up suggested that Aguero would not play again before November.
However, Aguero has suffered no ill effects after three days of training, including a full session with his team-mates on Thursday.
Guardiola was checking on his seven-goal top scorer during training on Friday before making a final decision, but was considering recalling him for Saturday's Premier League home match against Stoke City.
"He did his first training session after what happened, and he did it quite well," Guardiola said.
"Hopefully as soon as possible, he'll be back. Maybe on Saturday - today we're going to see the last training session and we'll see.
"Of course, he's not 100 percent, but he's recovered quite well. It's not as dangerous as it could be.
"He explained to us what happened, you think what might have happened, but now he's quite well and we're happy."
While Aguero is on the verge of a comeback, captain Vincent Kompany is continuing to struggle with injury problems.
The centre-back has not played since injuring his calf during Belgium's World Cup qualifying win over Gibraltar on August 31.
Kompany has been troubled by a series of injuries over the past three years, and Guardiola has refused to give him a return date.
"He is still injured. He's much, much better, but hopefully he's in the last part of his recovery," he said.
"His return depends on him. He'll notice how he feels and when he'll be able."