The Bath skipper is renowned for his unyielding approach to the game, but his aggressive style of play tends to get him into trouble on the odd occasion.
Grewcock holds the dubious distinction of being only the second-ever England rugby international to be sent off during a Test match after he received his marching orders against the All Blacks on England's tour of New Zealand in 1998 for excessive use of the boot.
And the lock missed his chance of making amends after he was ruled out of this year's England tour of NZ and Australia courtesy of a red card and a two-week ban for punching Lawrence Dallaglio in a Zurich Premiership clash.
But with discipline paramount in Woodward's set-up, Grewcock has declared that he is paying special attention to England's legal sessions.
"Referee Steve Lander has been drafted into the set-up and he is here with us to make sure we all know were we stand in terms of the laws," he said.
"The aim of the sessions are to allow us to play up to the very edge of the law and to make sure that we don't ever find ourselves on the other side of that line.
"Personally I'm very keen to get my head around the legal implications of the breakdowns, rucks and mauls. But as a team we know that we've got to watch ourselves in all areas.
"Kicking penalties is no longer a lottery, it's a science and we can't let anyone get a sniff of our posts."
The Bath man's hard-nosed attitude is by no means out of place in the England squad as coach Clive Woodward is planning to unleash a full-strength side for their opening RWC fixture against lowly Georgia, but Grewcock denies that such a tactic runs contrary to the spirit of the game.
"Georgia came through the qualifying stages and got to the World Cup on their own merit – they deserve to be there and I think it would be insulting and dangerous if we went easy on them. From what I've heard they're a tough bunch of boys."
But whether or not Grewcock will be part of that full-strength XV remains to be seen.
"Ben Kay has had a great couple of seasons so I've got my work cut out," said the Bath captain.
"But it will be tough for both of us and also for Martin Corry, who can also play lock. [With] Martin Johnson in there for sure the three of us will have to scrap it out for that vacant slot."
By Andy Jackson