A stomach virus has hit four Watford players ahead of their game against Crystal Palace tomorrow.

The Hornets are looking over their shoulder after losing four of their last five matches.

Gerard Deulofeu, the forward on loan from Barcelona, and defender Sebastian Prodl have both been absent from training due to the illness sweeping the camp.

Manager Javi Gracia did not wish to reveal the names of the other two players who were affected, but hopes all four will be fit for the visit of Roy Hodgson's side.

"Gerard was sick this week and there were other players who have been ill, too," Gracia said. "Prodl has also been ill all week.

"It is a stomach virus. They are recovered, available for the match and I am sure they are in the best condition."

The raft of illnesses will come as a dent to Gracia's preparations as his out-of-form Watford side attempt to halt their run of bad results.

Gracia enjoyed an impressive start to his tenure at Vicarage Road, but his side have taken just one point from the last 15 available.

Meanwhile, Jeffrey Schlupp is back in contention for Palace following his recovery from an ankle injury.

The full-back has returned to first-team training, but is not expected to start at Vicarage Road.

Scott Dann, Jason Puncheon, Bakary Sako and Connor Wickham remain long-term absentees.