The Hornets have made a couple of late moves in the transfer market ahead of their opening fixture with Andre Gray joining for a club record fee from Burnley, while Brazilian forward Richarlison has signed from Fluminense.
Silva's first task will be to halt the terrible end to last season, with Watford losing the last six matches of the 2016-17 campaign, although the Hornets have never won on the opening day of a Premier League season.
The Portuguese boss, who did beat Liverpool (2-0) as Hull manager last term, is sweating on the fitness of Troy Deeney and Christian Kabasele, who are both set for late fitness tests.
Barcelona transfer target Coutinho will play no part at Vicarage Road due to a back problem, with Jurgen Klopp admitting he may also sit out next week's Champions League qualifier against Hoffenheim.
Liverpool, who have won their last three meetings with Watford, should have captain Jordan Henderson available after a recent illness. Daniel Sturridge won't play due to a thigh problem, while Adam Lallana willbe out for at least two months out, also with a thigh injury.