Manchester United have confirmed that Manucho and Fabio Da Silva will not be making their first-team debuts because of injury.
Angola star Manucho, who gained his work-permit after a long legal battle in August, was pencilled in by United boss Sir Alex Ferguson to make his bow against Middlesbrough in the Carling Cup on Tuesday.
However, the striker has been unable to overcome a foot injury and so will not feature alongside the highly-rated Danny Welbeck, who will be given his first-start in a United shirt.
Brazilian full-back Fabio is also out of contention, but his twin-brother Rafael, who has already featured as a substitute, will make his first start for the club against Boro.
"I'm disappointed that Manucho hasn't recovered completely from a metatarsal injury, this would have been a good opportunity to look at him and Welbeck in combination," Ferguson revealed.
"I also have it in mind to look to youngsters like Jonny Evans, Darron Gibson, Danny Welbeck and Rafael, though unfortunately not his twin brother Fabio. He has a shoulder injury and is having an operation."
Ferguson will be using the game with Boro to experiment with his squad.
"My team will involve changes," he told United Review.
"There will be a mix of youth and experience.
"It's important that I give players coming back from injury some pitch time. The likes of Owen Hargreaves, Ji-sung Park, Nani, Anderson and Cristiano Ronaldo all need games and they could be involved either in the starting line-up or on the bench."
United assistant Mike Phelan later stated that Manucho was indeed in the squad to face Boro.
"Manucho is in a squad of 20," said Phelan.
"We shall get down to the nitty gritty tomorrow and pick a team."