Alessandro Diamanti could make his debut for Watford if he receives international clearance on time, while Nathan Ake is expected to be on the bench after signing on loan from Chelsea earlier this week.
Miguel Britos and goalkeeper Giedrius Arlauskis are also both available to make their first appearances for the Hornets after serving bans given at their previous clubs.
Southampton, meanwhile, are without Ryan Bertrand (knee), Jordy Clasie (hamstring) and long-term absentee Fraser Forster (knee).
Ronald Koeman will assess the rest of his squad after their draw against FC Midtjylland in the Europa League on Thursday.
Kick-off at Vicarage Road on Sunday is at 4pm.
Watford have lost just one of their last six competitive meetings at Vicarage Road against Southampton (W4 D1 L1).
However, in the last season that these two sides met (2011-12), Southampton won both home and away without conceding a goal in either match.
No side are on a longer current run of failing to keep a clean sheet in the Premier League than Southampton (eight games).
Saints have won just one of their last eight Premier League games (W1 D2 L5), conceding in every one of these matches.
It took Quique Sánchez Flores until his fourth Spanish Liga game as a manager before he picked up his first victory (losing the first three) – this will be his third Premier League game after drawing the first two.
The next goal scored at Vicarage Road will be the 100th Premier League goal scored at the home of Watford.
Just two of Graziano Pelle’s 13 Premier League goals have come away from home.
Southampton have picked up eight yellow cards in their opening two PL games of the season – it took them five games to accumulate this total in 2014-15.
Watford have made more interceptions than any other side in the Premier League in the opening two matches (58).
Troy Deeney has only scored two goals in his last 10 appearances for Watford, whereas team-mate Matej Vydra has scored in six of his last 10 games for the club (six goals).
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