The 20-year-old was stretchered off in the second half as Schalke were defeated 3-2 by Augsburg in the Bundesliga on Sunday.
Advertisement
Van den Berg, who has made three appearances for the German side since his move, was taken to hospital shortly afterwards.
The Dutchman attempted to block a shot from Mergim Berisha but sustained a nasty ankle injury in the process.
Schalke shared in a tweet: "Sepp van den Berg is on the way to the hospital with a suspected ankle injury. We keep our fingers crossed for you, Sepp!"
Advertisement
The club later posted an update confirming he would be out until next year.
A statement said: "Two players suffered injuries in the 3-2 defeat against FC Augsburg on Sunday (2nd October).
"Sepp van den Berg was diagnosed with a serious ligament injury, while Rodrigo Zalazar suffered a metatarsal fracture in the game against the Fuggerstädtern.
"The injuries mean that both players will be unavailable for the rest of Schalke's competitive games this calendar year."
Advertisement
Advertisement
Before moving to the Bundesliga on-loan, the centre-back made four senior appearances for the Reds having joined Liverpool from Dutch side PEC Zwolle in 2019.
He then spent 18 months on-loan at Preston North End, making 66 appearances in total.
Returning to Merseyside in the summer, he opted against a move back to the Championship in favour of a switch to Germany.
Advertisement
In an interview with ELF Voetbal in his native Netherlands, Van den Berg admitted he felt he needed to test himself above the Championship.
"Over the last year-and-a-half I gained a lot of experience at Preston," he said.
"Just look at my shoulders. I have gained 10 kilos, only muscle mass!
Advertisement
"Another year in the Championship was not my preference. I spoke with Burnley, but I still wanted a step higher. The Bundesliga was my preference."
The Netherland's under-21 star, who signed a new deal at Anfield in August until 2026, will be hopeful of a speedy recovery as he aims to break into Jurgen Klopp's side next season.