Nyron Nosworthy faces a battle to play again this season having undergone surgery on a ruptured Achilles sustained while on international duty.
Watford are not putting a date on the influential defender's return, but he is now certain to face a lengthy spell on the sidelines.
Nosworthy picked up the injury while representing Jamaica in their clash against Panama last Friday and was back in London on Monday to undergo an operation.
The procedure was a success and Hornets boss Gianfranco Zola will be hoping to have Nosworthy back in the fold as soon as possible, with Watford embroiled in a promotion scrap over the remaining five-and-a-half weeks of the season.
Elsewhere, playmaker Almen Abdi faces a fitness race of his own to be involved in the Easter double-header against Burnley and promotion rivals Hull having spent the international break recovering from his groin injury.
Goalkeeper Manuel Almunia is making good progress in his lengthy recovery from a hamstring problem but will also need to be assessed ahead of the weekend to determine his level of fitness.