The Argentine defender has only played 142 minutes this season amid continued injury complications which have failed to abate since he ruptured knee ligaments in April 2017.
Man United are keen to find a reliable partner for Victor Lindelof at the back, and Koulibaly – one of the best defenders in Europe at the moment – has been earmarked as the club’s primary target ahead of the summer transfer window.
And according to Ducker, the club is willing to sell Rojo to make way on its wage bill for Koulibaly.
However, the Argentine’s continued injury problems have complicated the prospect of a move in January, making any deal this month unlikely.
Napoli are deeply reluctant to negotiate mid-season, especially for a player of Koulibaly’s value, but a summer deal is certainly possible, with the Senegalese defender reportedly open to moving to Old Trafford in the summer.
Inter Milan’s Milan Skriniar and Porto youngster Eder Militao are other defensive options being tracked by United ahead of the summer.
It seems clear that Rojo will be the first casualty of a much-needed transformation of United’s unreliable defensive options once the 2018/19 campaign is over.