The 28-year-old right-back suffered a serious ligament injury in his left ankle during the 3-0 victory against Borussia Mönchengladbach.
Following an examination by a specialist, it has now been determined that surgery is unavoidable. According to the report, the club is even anticipating that he will miss the rest of the season.
This means he will definitely miss Denmark's crucial playoff matches to qualify for the World Cup.
He was already suspended for the first match against North Macedonia, and now he will also miss a possible final match against either the Czech Republic or Ireland.