Another central midfield option is highly-rated Sporting Lisbon star William Carvalho. The exciting 22-year-old has been on the Red Devil's radar since June and has also attracted interest from Monaco, Chelsea and Real Madrid. Van Gaal sees Carvalho as an alternative to Arturo Vidal this summer and is considering activating his £37.5 million release clause. United have a positive relationship with Sporting and have done business with the Portuguese side in the past, signing both Cristiano Ronaldo and Nani. That tie could help them in their efforts to land Carvalho, who plays in defensive midfield. This is an area where the Reds have had issues in the past, issues which were hardly solved by last summer's acquisition of Marouane Fellaini, who has flopped since joining from Everton. United's midfield was at times overrun last season and the addition of steel to the engine room would give van Gaal a good platform of which to launch a title defence off in 2014-15. They face fierce competition for his services however with domestic rivals Arsenal becoming the latest to show an interest in the Portugal international recently, though a deal to bring Carvalho to Old Trafford would certainly be a coup.