Director of football strategy Damien Comolli watched the 26-year-old in action last week and was suitably impressed.
On the radar: Osasuna defender Nacho Monreal (left)
Monreal, who has four full caps, suffered a bad knee injury in December but has come back strongly. He was on Liverpool's list of summer targets and came under Arsenal's scrutiny prior to his injury.
Desperate to plug their problem left back position, Liverpool decided against a loan move for Aston Villa's Stephen Warnock in January and cooled their interest in Wigan's Maynor Figueroa but they have watched Newcastle's Jose Enrique and Celtic's Emilio Izaguirre.
Monreal would not come cheap, however, as Osasuna value him at about ?9m.
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