England captain Lewis Moody will be given every chance to prove his fitness for the Rugby World Cup after suffering a mild ligament strain in his right knee.
Moody's leadership is seen by the England management as "vital" and they have not ruled out naming him in their final 30-man squad on August 22, even if he is not 100% fit.
The Bath flanker, who is wearing a heavy-duty knee brace, was injured when 18-stone team-mate Tom Palmer fell on his leg during England's 23-19 World Cup warm-up win against Wales last Saturday.
Moody will definitely not play in the reverse fixture at the Millennium Stadium this weekend and no target date has been set for his return to action.
But the England medics are "optimistic of his progress" and scrum coach Graham Rowntree confirmed the squad need Moody involved at the World Cup if at all possible.
"Is it realistic he will be on the plane (to the World Cup)? It is too early to say with that injury," said Rowntree.
"We will give him the time he needs. He is vital for us going forward. He has led from the front, led with energy and the guys respect him for that. He is doing a great job.
"We will see how he develops over the next few days. Our medics are fantastic here, they have worked wonders before.
"It is a mild strain, not a bad strain, which gives us hope.
"We don't have a hard and fast rule (about taking injured players).
"It won't be the first World Cup squad to potentially take players who are injured - but those kinds of decisions we'll make nearer the time when we know how the injury has settled down."
England manager Martin Johnson will finalise his World Cup squad, including the identity of the captain, during a dinner at Twickenham on August 22.
In 2003, Lawrence Dallaglio played every game of England's triumphant World Cup campaign having not been involved at all in the immediate build-up.
In that same tournament, Richard Hill was injured in the opening game against Georgia and did not play again until the semi-finals but England kept him in the squad because he was considered invaluable.
Moody appears to occupy a similar position within the current England squad, despite having played fewer than five matches since originally damaging his knee playing for Bath in January.
"The way he has trained and the way he has led the standards in training, the way he has led the group, it is not like he has been out for eight months," said Rowntree.
"He is exceptionally fit, keen and raring to go. He is in very good nick and was going well until he was taken off the field at the weekend.
"On Saturday night he was optimistic he would get better and he was walking about the day after, which is always a good sign in my book.
"Would he be missed? Of course he would, but let's cross that bridge when we come to it."
England will shuffle their deck for Saturday's game and the chances are Moody would not have played anyway, with Johnson needing to run the rule over back-row options Hendre Fourie and Chris Robshaw.
But Andrew Sheridan is definitely out as he continues his recovery from shoulder surgery while Ben Youngs and Shontayne Hape are still not in peak condition after summer operations.
Ben Foden is set to reclaim the full-back jersey in Cardiff but he is beginning to feel the pressure - not only from rival Delon Armitage, who laid down the gauntlet with his performance last weekend, but because of what is at stake.
England's World Cup campaign kicks off on September 10 - one month tomorrow.
"Delon's a good friend of mine so it's good to see him back playing, and playing so well, but it definitely puts the pressure back on myself and the ball is back in my court," said Foden.
"When I get a chance to put the shirt back on I need to perform well. Delon's getting back to the form he showed in 2009 and I've got to make sure I match that and keep my nose ahead.
"There's more pressure than ever on me this weekend.
"It'll be a hostile environment going down to Cardiff. I really enjoy that pressure and that centre stage."