Louis van Gaal has been left reeling by the news that he will be without Wayne Rooney for the biggest match of Manchester United's season so far.
Despite being substituted in the 68th minute with a knock, Rooney seemed in no discomfort at all when he walked out of the King Power Stadium last Saturday following United's 1-1 draw at Leicester.
But Van Gaal revealed yesterday that the striker had suffered a "nasty" ankle injury that will keep him out of today's home match against West Ham and the crunch Champions League match at Wolfsburg three days later.
United need to win at the Volkswagen Arena next week to guarantee their passage to the last 16 of the Champions League.
And even though Rooney has not been in sparkling form this season, his experience and presence will be missed in Germany next week. "It's a nasty injury," the United manager said of Rooney, who has played 499 times for the club.
"He shall not play his 500th game (on Saturday) because he is more injured than I thought.
"His ankle is not good enough and we have to recover that ankle with a lot of strength. He has to do a lot of exercises to make his ankle stronger. He needs more time."
When asked if Rooney would miss the match at Wolfsburg, Van Gaal said: "Yes, I think so."
Van Gaal also confirmed defender Marcos Rojo would be sidelined for a number of weeks after dislocating his shoulder in training.
The Argentina left-back suffered the same problem last November in the 1-0 defeat at Manchester City and had only just returned to training following another injury.
"He was recovered of his (previous) injury so he trained with us on Wednesday after we gave all the players two days off," Van Gaal said.
"He started fresh with us but he fell down and it was a bad fall and he dislocated his shoulder.
"It's more or less the same as what happened last season (at City) so he is for more weeks out.
"Whether he shall be operated on is a question for Marcos and the doctor. We have to wait for the scan. We have to make the scan at the proper time."
Van Gaal conceded Ander Herrera and Phil Jones, who missed the last two games with hamstring and ankle injuries respectively, would not be fit for the visit of the Hammers today.
The only good news for Van Gaal from the treatment room is that midfielder Jesse Lingard has overcome a hamstring injury and is fit to face Slaven Bilic's side.
Given that Luke Shaw and Antonio Valencia are out with long-term leg injuries, Van Gaal's squad is looking extremely thin going into a crunch period in which is team will play seven games in 30 days. That means Van Gaal could be persuaded to dip into the January transfer market, though he concedes signing the players he wants next month will be difficult.
"The problem is when you see our injuries, they are always contact injuries and you cannot avoid that because football is a sport of direct resistance," Van Gaal said.
"Shaw is directly injured, Rojo also, and Wayne also, so we have a lot of contact injuries and long-lasting injuries, that is our problem so we are looking (to sign players) but it is not so easy to buy and in January it's more difficult. We are looking but it is not that it is for sure."
United missed the chance to move to the top of the table by drawing at in-form Leicester last weekend. Van Gaal was not giving any clues away about whether he would revert to a back four after sending United out in a 3-4-1-2 formation at Leicester.
"It depends on the opponent and the shape of the players, I have to compare," he said.