Albert Riera has been fined and handed an additional one-match suspension by the FA for his behaviour following his red card against Charlton Athletic.
The Spaniard was dismissed against the Addicks after receiving a second yellow card in the 78th minute of the contest.
The 32-year-old failed to immediately leave the pitch after being sent off and the FA deemed his behaviour as improper conduct.
Should Riera remain with Watford next season, he will miss the first game of the 2014/2015 campaign.
The former Liverpool winger also received a £2000 fine.