Mason Mount and Willy Kambwala are set to be ruled out of Manchester United's FA Cup semi-final against Coventry City, talkSPORT understands.
The pair are the latest Red Devils stars to pick up injuries and did not board the train with the rest of the team to travel down to Wembley.
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Sofyan Amrabat was also absent for the journey down from Manchester.
As a result, Erik ten Hag has added 18-year-old Louis Jackson to the senior squad from the club's Under-21s team.
The Red Devils youngster has never made a first-team appearance.
Kambwala's absence means Harry Maguire will be the only senior centre-back available for Man United.
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According to football transfer expert Fabrizio Romano, Erik ten Hag had to test midfielder Casemiro as a centre-back with Maguire as an emergency solution.
The England international also nursed an issue during the 2-2 draw at Bournemouth.
Other centre-backs Lisandro Martinez, Victor Lindelof, Raphael Varane and Jonny Evans are out injured for Sunday's clash, which is live on talkSPORT.
Mount's first season since leaving boyhood club Chelsea for Old Trafford for £55million has been marred by injury issues, missing 27 games in total.
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He's played less than one half of football in five appearances since returning from injury in the 4-3 win against Liverpool in the FA Cup quarter-final on March 17.
That includes 32 minutes in the Premier League, including his cameo and only goal this season in the 1-1 draw against Brentford and 15 minutes in the FA Cup.
There have now been more than 60 separate cases of injury or illness in the Man United squad this season.