Manchester United defenders Rio Ferdinand and Rafael da Silva face lengthy layoffs after they both picked up injuries.

Right back Rafael will miss the first 10 weeks of the season after dislocating a shoulder in training ahead of Sunday's opener against West Bromwich Albion.

And during United's 2-1 victory, Ferdinand sustained a hamstring injury that manager Alex Ferguson said will rule the England center back out for six weeks.

Ferdinand is set to miss the league games against Arsenal and Chelsea, along with England's 2012 European Championship qualifiers against Bulgaria and Wales next month.

Ferdinand's central defensive partner Nemanja Vidic could also be sidelined after he came off with a calf injury.

''We don't know if it's just a nerve or something, but he could be out for a couple of weeks,'' Ferguson said of the Serbia captain.