Will Hughes also starts in midfield alongside Conor Gallagher and Eberechi Eze, and Jack Butland is named between the sticks.
The outfield four replace Jeffrey Schlupp, James McArthur, Jordan Ayew and Jean-Philippe Mateta as Vieira fields an attacking lineup in pursuit of a third game unbeaten.
Watford have made four changes to the team which lost a crucial game against Burnley.
The Hornets must win today to avoid relegation, and former Palace manager Roy Hodgson has fielded Joshua King, Tom Cleverley, Craig Cathcart and Edo Kayembe in place of João Pedro, Christian Kabasele, Juraj Kucka and Imran Louza.
Palace: Butland, Clyne, Andersen, Guéhi, Ward, Hughes, Gallagher, Eze, Zaha, Olise, Edouard.
Subs: Matthews, Mitchell, Milivojević, Tomkins, Kouyaté, Schlupp, Ayew, Mateta, Benteke.
Watford: Foster, Kamara, Samir, Cathcart, Femenía, Kayembe, Cleverley, Sissoko, Dennis, King, Sarr.
Subs: Bachmann, Gosling, Masina, Kabasele, Ngakia, Etebo, Ekong, Sema, Kalu.