The veteran Frenchman is looking likely to leave Old Trafford at the end of the season when his contract expires, which will leave the Red Devils with only Alexander Buttner to call upon to occupy the left-back role.
Southampton’s Luke Shaw is rumoured to be the top target, yet a deal for the £30m-rated teenager may be difficult to force through with the likes of Chelsea also interested.
As a result United are considering other options, and Schalke’s 20-year-old Bosnian has emerged as a target.
Kolasinac has been one of the German side’s most promising performers in recent times and has been a regular starter this term.
Unlike Shaw, the Eastern European is unlikely to cost a fortune, with the Gelsenkirchen outfit rumoured to be open to offers of around £4.5m.
Despite having just two senior international caps to his name, the starlet may well represent Bosnia and Herzegovina at the World Cup later this year after being included in their most recent squad.