Watford have reportedly made a €7.2m offer for FC Porto defender Bruno Martins Indi.

The Hornets are still looking to bring in another centre-back and reports in Portugal claim the Premier League side have made a bid for the Netherlands international. 

New Watford head coach Walter Mazzarri has been playing a 3-5-2 formation during pre-season and is believed to be keen to add one more defender to his squad ahead of the new season next month. 

Martins Indi, 24, made 34 appearances for Porto last season and has reportedly attracted the interest of several English clubs including Everton.

The 6ft 2in defender could be an attractive proposition for Mazzarri although the Hornets, who appear to have a number of potential options, have also been linked with Arsenal's Calum Chambers.