Huddersfield striker Elias Kachunga could spend the next three months on the sidelines.
The German was stretched off after colliding with Watford goalkeeper Heurelho Gomes during the Terriers 4-1 victory at Vicarage Road.
"Subsequent scans have confirmed that 'Kache' has damaged his medial collateral ligament and, ahead of a visit to a specialist on Monday afternoon, he is provisionally expected to be sidelined for an estimated 8-12 weeks," the Terriers said on their official website.
Kachunga has been a regular of David Wagner's side in the Premier League this season and has made 19 appearances across all competitions.