Watford will be without midfielder Tom Dele-Bashiru for the rest of the season because of an ankle injury.
The 23-year-old has not played since damaging ankle ligaments in the 4-0 defeat at Swansea on 30 December.
At the time, he was expected to be out for "a couple of months" but has picked up another ankle problem in training.
Watford have also said midfielder Edo Kayembe will be out for "the same period" with a calf strain that means he could miss the rest of the campaign.
Kayembe, 24, has been out of action since 12 November, having played 22 games this season to that point.