Manchester United are interested in signing Barcelona defender Javier Mascherano, [football] direct news understands.The Argentine international joined Barca in 2010 and has become a big part of the Catalan side’s recent success, occupying a centre back role rather than his usual midfield position.googletag.cmd.push(function() { googletag.display(“div-gpt-ad-1389116196215-0”); });Appearing in 30 games this season for Barcelona, Mascherano is one of Tata Martino’s first names on the team-sheet, however, reports of a summer overhaul has seen the former Liverpool man linked with an exit.Manchester United are also considering a summer of signings as they look to improve after a dismal first season under David Moyes.[FDN] understands that United admire Mascherano’s workrate and battling nature and would like to add him to their midfield options.Italian side Napoli are also said to be interested in the 29-year-old.