The BBC claim that there has been no further progress on tying the trio down to new deals, with their contracts expiring this summer.
The young trio are all out of contract this summer and as such have been free to sign pre-contract agreements with other clubs since the turn of the year.
The report claims that United have refused to discuss the respective players’ futures, with it unclear where they will play their football next season.
McNair and Blackett have been surprise additions to the first-team squad this season under Louis van Gaal, but have been called upon due to a spate of injuries to the side’s first-choice centre-halves.
Both youngsters have made nine Premier League appearances this season for the Old Trafford side, but have found their opportunities limited of late due to the return of the likes of Daley Blind, Chris Smalling and Phil Jones.
Belgian-born Pereira signed for the historic club from PSV Eindhoven in 2011, but the 19-year-old is yet to make his Premier League debut for United.
The teenager arrived with much promise, and made his debut for adopted country Brazil at under-20 level last year.