Borja Valero is poised to complete a permanent return to Spain from West Brom after agreeing a five-year deal with Villarreal.
The midfielder failed to make the breakthrough at the Hawthorns having been signed in a club-record £4.7million four-year contract from Real Mallorca in 2008.
Valero spent just one campaign with the Midlands outfit before heading back to his former club on a season-long loan last term.
The 25-year-old shone back in his homeland, winning the prestigious Don Balon award for the best Spanish player.
And he is now on course to sign a long-term deal with Villarreal once he has completed a medical with the Primera Liga outfit.
A statement on the Villarreal official website read: "Barring a few minor details, Villarreal CF and West Bromwich Albion have come to an agreement for the transfer of footballer Borja Valero, who will belong to the Yellow Submarine club for the next five seasons.
"After the signing of the contract and the medical tests, the club will make official the date of the presentation of the footballer."
West Brom confirmed Valero had been given permission to open talks with Villarreal.
A West Brom club statement read: "Valero has been given permission to travel to the Spanish club for a medical and to train with them while discussions continue.
"He rejoined West Brom for pre-season training last weekend following a season-long loan in La Liga with Real Mallorca.
"But after returning to Albion, he has expressed a strong desire to continue his career in Spain for professional and family reasons.
"Albion rejected an offer from Sevilla for Valero last month but agreed to meet Villarreal yesterday for talks on a possible deal. This dialogue is ongoing."