Belgium midfielder Axel Witsel was the subject of Jose Mourinhos scouting mission in Belgium last week.
Mourinho was spotted in the stands during Belgiums 2-0 victory over Iceland with some reports speculating the Manchester United boss was there to scout long-term transfer target Toby Alderweireld.
United failed in a bid to sign the Tottenham defender in the summer, but are being tipped to resurrect their interest in Alderweireld in January.
But Belgium outlet HLN claim Mourinho was actually in attendance to get a close-up look at Borussia Dortmund star Witsel.
United were linked with Witsel last summer before the 29-year-old joined Dortmund in a £18million deal.
Witsel was thought to be the clubs preferred choice while Mourinho was more keen on the prospect of signing NGolo Kante from Chelsea.
But Mourinho has now changed his tune and is plotting a January move for Witsel.
United are ready to offer Dortmund a profit on the investment they made in Witsel in the summer, but it will be difficult to prize the defensive midfielder away from Germany.
Witsel is yet to miss a game for Dortmund this season, starting ten of his eleven Bundesliga appearances.
Dortmund are four points clear at the top of the Bundesliga table and Witsel has been a major part of their resurgence this season.
The Germans want to maintain their title push and are aiming to keep hold of all their players in the January window.