Luke Shaw is struggling with a foot injury that has sidelined him for two of Manchester United's last three games.
Shaw has not played since he was substituted at half-time in the 4-0 thrashing by Brentford on August 13 and he was absent from the matchday squads against Leicester and Real Sociedad.
The 27-year-old was in line to start against Sociedad but did not participate in United's open training session the day before the Europa League defeat.
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It is understood Shaw's injury is believed to be minor and United manager Erik ten Hag said the left-back had a "small complaint".
Ten Hag wanted to include Shaw in the 20-man squad at Leicester but the defender was still struggling with his injury and United had to name two goalkeepers on the bench.
Shaw missed the last eight games of last season as he had surgery to remove screws that were inserted to repair the double leg break he suffered against PSV Eindhoven in September 2015.
The timing of Shaw's unavailability could affect his chances of an England squad inclusion, with manager Gareth Southgate due to announce his party for this month's Nations League ties with Italy and Germany on Thursday.
Shaw missed England's four Nations League matches in June through injury and this month is the last get-together for the national team before their World Cup opener against Iran on November 21.
Although England have a shortage of out-and-out left-backs, Shaw has been ousted from the United side by summer signing Tyrell Malacia. Malacia, 23, has started in United's last five games and Shaw was an unused substitute against Liverpool, Southampton and Arsenal.
Shaw's England competitor, Ben Chilwell, has only started in two of Chelsea's seven matches this season and their new manager Graham Potter has been reunited with £60million signing Marc Cucurella, whom he developed at Brighton.
United travel to Moldova to face FC Sheriff on Thursday and the Premier League is yet to clarify if the visit of Leeds will go ahead at Old Trafford next Sunday, even though the Queen's funeral will be held on Monday and 204 miles away at Westminster Abbey.
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