Watford captain Troy Deeney looks set for his first appearance of the season in the Carabao Cup against Bristol City.
The striker missed the Premier League opener against Liverpool as he recovered from a pre-season groin operation and was an unused substitute at Bournemouth on Saturday.
Etienne Capoue and summer signing Will Hughes are also pushing for their first starts of the campaign.
Younes Kaboul, Daryl Janmaat, Roberto Pereyra, Tommie Hoban, Craig Cathcart and Mauro Zarate are out injured.
Aden Flint is included in the City squad as Robins boss Lee Johnson prepares to make changes for the second-round tie.
Flint has not played since coming on as a substitute on the opening day of the season amid speculation linking the centre-back with a move to Birmingham.
Loan signing Cauley Woodrow is cup-tied having already played for Fulham in the competition, while Matty Taylor and Milan Djuric remain absent with groin injuries.
So City have just two fit strikers available at Vicarage Road, record summer signing Famara Diedhiou and teenager Freddie Hinds.