Wigan have announced Uwe Rosler as their new manager after agreeing compensation with Brentford.
Marseille have parted company with manager Elie Baup in the wake of Friday's defeat to Nantes at the Stade Velodrome.
The Spanish club, also owned by Watford supremos the Pozzo family, confirmed on their website that Iriney has agreed a season-long deal at Vicarage Road.
The 32-year-old has spent more than 10 years in Spain and also played for Rayo Vallecano, Celta Vigo, Real Betis and Almeria.
Watford caused controversy last season by bringing in a host of loanees from Granada and the other Pozzo-owned club, Udinese.