Manchester United defender Phil Jones is not expected to play until the end of August as he is suffering from "mild thrombosis".
The 23-year-old former Blackburn Rovers star missed Saturday's unconvincing 1-0 victory against Tottenham at Old Trafford because of the problem which is the formation of clotting of the blood in a part of the circulatory system.
The England international played in United's pre-season tour of the United States and trained in Manchester this week but is not expected to play his first Premier League match for three weeks.
United beat Spurs thanks to Kyle Walker's early own goal but they struggled for fluency throughout.
Meanwhile, United boss Louis van Gaal spoke about David De Gea's future after the match.
Van Gaal did not pick the goalkeeper in his starting line-up as De Gea continues to be linked with a move to Real Madrid, and said after the Spurs game: "I'm not the most important part with De Gea. The most important part is the player and the club who wants to buy him.
“He's our best player for the past two or three years so we cannot let him go so easily. We want to sell at the same level as we pay. We want to keep him of course."
United's next game is against Aston Villa, who beat Bournemouth 1-0 in their opening fixture, on Friday. United can be backed at 1/1 to win the match while a victory for Tim Sherwood's side is available at 1/1.
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