Manchester Untied are casting an eye over long-term target Guilherme Siqueira, [football] direct news understands.United have been keen on making a move for the Brazilian full-back for some time but a failed last summer after he agreed a loan move to Benfica.googletag.cmd.push(function() { googletag.display(“div-gpt-ad-1389116196215-0”); });However, after consistent performances this season for the Portuguese out-fit, United remain interested on looking at his current situation.Siqueira, who is on loan from La Liga side Granada could join Benfica on a permanent basis for as little as 7m.But if they fail to take up the option then he will return to Spain and be made available for transfer.[FDN] understands that United officials were casting an eye over the 27-year-old as Benfica visited Tottenham Hotspur at White Hart Lane on Thursday.