Ferguson's central-defensive stalwarts both limped off during the second half of the first match of United's Barclays Premier League title defence - a 2-1 win at West Bromwich Albion.
Ferdinand appears the most serious, sidelined for six weeks with a hamstring problem that also means he will miss England's Euro 2012 double-header against Bulgaria and Wales in September, as well as the start of United's latest Champions League quest.