United have regularly scouted the Southampton and England full-back Nathaniel Clyne, with the 23-year-old's progress over the past 18 months seeing him emerge as a target. And the Athletic Bilbao centre-half Aymeric Laporte - a 20-year-old France Under-21 international - has also been repeatedly monitored by United. Van Gaal always has a ball-playing centre-half in his sides and he remains a confirmed admirer of Borussia Dortmund's Mats Hummels, who would fit this bill.