Watford defenders Younes Kaboul and Sebastian Prodl and midfielder Valon Behrami are all doubtful for this weekend because of injury.
Miguel Britos is suspended, but Troy Deeney is expected to start after only being used as a substitute last week.
Swansea will be without captain Jack Cork, who sprained his ankle during the defeat by West Ham on Saturday.
However, top scorer Fernando Llorente is pushing for a recall after coming on at half-time in that fixture.
MOTD COMMENTATOR'S NOTES
John Motson: "This is a far bigger game for Swansea. Watford can consider themselves almost safe and look forward to another season in the Premier League.