England captain Jonny Wilkinson has admitted his knee injury is worse than first thought, making it less likely he will be able to play any part in the RBS 6 Nations.
The Newcastle Falcons fly-half sustained ligament damage in his left knee in the recent European Cup match away to Perpignan.
Initially, the injury was diagnosed as a minor tear, with a standard recovery time of four to six weeks.
But it is now feared Wilkinson will need six to eight weeks to recover.
The most optimistic outcome may enable him to return for England's matches against Italy on March 12 and Scotland on March 19, both at Twickenham.
But, if ruled out for eight weeks, a return to the international game before the British and Irish Lions' tour to New Zealand would be impossible.
Wilkinson is unable to practise his kicking, and told The Times: ''It could drive me insane not being able to practise the kicking, but I have accepted that this is the case and am trying to keep it in the back of my mind.
''I am off crutches now but walking is still hampered. I can only just walk, so I know I can't kick.
''It would have been harder having to stop myself from kicking if it had just been a slight strain.''