MANCHESTER, ENGLAND - MARCH 12: Rafael Da Silva of Manchester United and Abou Diaby of Arsenal battle for the ball during the FA Cup sponsored by E.On Sixth Round match between Manchester United and Arsenal at Old Trafford on March 12, 2011 in Manchester, England. (Photo by Clive Mason/Getty Images)
Update: Sir Alex Ferguson revealed after the match that Rio Ferdinand will miss 6 weeks and that Nemanja Vidic will miss a fortnight.
Manchester United defender Rafael da Silva will miss around 10 weeks of action after suffering a shoulder separation at Carrington during training. Injuries in defense is certainly a concern for the Reds with Patrice Evra missing the opening match due to injury versus West Bromwich Albion . The concern became compounded with captain Nemanja Vidic and Rio Ferdinand leaving the match at the Hawthorns due to injury. Possible options at right-back include Chris Smalling, who deputised there today, along with twin brother Fabio and Phil Jones. United finished Sunday's match with Fabio at left-back, Jones and Jonny Evans at center-back, and Smalling at right-back. The extent of Vidic's and Ferdinand's injuries are unknown at the moment but each was able to walk off the pitch without assistance. Over the next two weeks, the club faces likely title-contenders Tottenham Hotspur and Arsenal FC -- United may be forced to do it with their young, but promising defenders.