Erik ten Hag’s men have endured a challenging start to the season, with off-field issues compounded by poor performances and results on the pitch.
Wan-Bissaka was named on the bench having dealt with illness in the build-up and then picked up an injury when brought on as a 85th-minute substitute.
United said in a statement: “Aaron Wan-Bissaka is set for a period on the sidelines after sustaining an injury during the closing stages of Saturday’s game against Brighton and Hove Albion.
“Further assessment will be needed to determine how long Wan-Bissaka will be out for, but initial indications suggest it will be several weeks.”
It has been reported that Wan-Bissaka is facing two months out as the right-back joins United’s lengthy list of absentees.
Left-backs Luke Shaw and Tyrell Malacia are out along with centre-back Raphael Varane, while deadline-day signing Sofyan Amrabat has to make his debut due to a knock.
Mason Mount has not featured since picking up an injury in last month’s loss at Tottenham, while Kobbie Mainoo, Amad Diallo and Tom Heaton are also sidelined.
Jadon Sancho has been banished from the first team “pending resolution of a squad discipline issue” and Antony has been given a leave of absence following assault allegations against him.
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