Watford centre-back Joel Ekstrand has been ruled out for the rest of the calendar year with an anterior cruciate ligament injury.
The Sweden international damaged his knee in the first half of Saturday's 1-0 defeat to Ipswich Town.
"He caught his studs in the turf and has damaged his cruciate ligament in his left knee," Watford's head of medical Richard Collinge told the club website.
"He'll have surgery in a week or so's time, then it's rehab after that. The feeling for this type of injury is around the nine months mark to get back."
Ekstrand had scored one goal in 24 Championship appearances for the promotion-chasing Hornets this season.