Watford goalkeeper Daniel Bachmann will be out for up to three months because of an ankle ligament injury.
The 30-year-old Austrian went down near the end of Saturday's 2-1 home defeat by Sheffield United.
Boss Tom Cleverley ruled out a dislocated ankle or ruptured Achilles tendon following the game.
But he told the club website on Monday: "It's not as serious as we might have first feared, but whichever way we choose to rehabilitate him we're talking two or three months and not weeks.
"Dan felt at the time that something had cracked or popped, and you can see why he'd have had those sensations at the time.