The Northern Echo says the Teessiders are understood to have made an initial inquiry to Villarreal regarding Riquelme's possible availability.

The Spanish club have told Boro that the 29-year-old midfielder, who still has two years of his current contract to run, is available for £10 million and chief executive Keith Lamb is paving the way for a formal offer.

Tottenham are also interested in the Argie, which was confirmed by his agent last week.