World Cup winners Sergio Ramos and Bastian Schweinsteiger are on Manchester United's list of summer targets, according to Sky sources.
Weekend newspaper reports claimed United are demanding Real Madrid's long-serving defender Ramos as part of any deal for goalkeeper David De Gea.
The 29-year-old has two years to run on his Real contract and fits the profile of the experienced defender Louis van Gaal is seeking as part of a summer recruitment drive.
Ramos' haul of honours also includes two European Championship titles, a Champions League and three Spanish titles and he is capable of playing at right-back or even in midfield as well as his regular centre-half role.
Van Gaal is also seeking at least one centre-forward and a midfielder in the ball-playing mould of Michael Carrick.
That description applies to Schweinsteiger, the Germany midfielder who made just 15 Bundesliga starts for Bayern Munich last season.
It is understood the 30-year-old is also on the radar for United, whose sole signing so far this summer is Holland winger Memphis Depay.