captain Troy Deeney will miss the club's pre-season trip to Austria as he continues his recovery from injury.
The 29-year-old striker has had surgery on a minor groin problem and will remain in the UK for a short rehabilitation period, according to the Premier League side's official website.
Deeney, who is once again being linked with a move away from Vicarage Road, with West Brom reportedly interested, scored ten league goals last season.
He is the only notable absentee from the 31-man squad named by new Hornets head coach Marco Silva, which includes recent signings Will Hughes and Nathaniel Chalobah.