Wilfried Zaha may return to the Palace starting line-up after scoring the winner last week against Southampton.
Manager Patrick Vieira says some academy players could feature before the end of the season.
Watford will assess Tom Cleverley and Craig Cathcart, who both missed last week's defeat at Burnley because of injury and illness respectively.
Manager Roy Hodgson is suffering from shingles but is expected to be in the dugout on his return to Selhurst Park.
LAWRO'S PREDICTION
It's nice that Watford boss Roy Hodgson is going back to Selhurst Park in the week that he has announced this will be his final season in management.