The Sun reported earlier in the week that the Royals had offered £1.5 million to sign the Hornets central defender, with some sources on Twitter claiming a bid had been accepted from the Premier League-bound team. Mariappa was also named Watford's player of the season.
Fellow Premier League sides Bolton and Newcastle are also keen on the 25-year old, with the Magpies almost snatching Mariappa up in the January transfer window but a narrow deadline stopped the transfer. Adrian has spent his whole career with Watford, completing over 200 games.