Dylan Hartley, who will be named as England's captain for the Six Nations on Wednesday, has been ordered to improve his tackling technique in an effort to prevent a repeat of the six-week suspension he received after being sent off for swinging his arm at the head of Leinster flanker Sean O'Brien.
Hartley underwent a Test-match simulated fitness test on Thursday to prove to head coach Eddie Jones he is fit to lead England for the Six Nations opener against France on Feb 4 despite playing just six minutes of rugby in more than two months.
Jones revealed that England have been working on Hartley's tackle technique during his suspension - he is free to play again on Jan 23 - to reduce the risk of further red cards following World Rugby's crackdown on dangerous play.
"More cards are not inevitable," said Jones, who arrived with his England squad in the Algarve today for a five-day training camp. "It comes down to technique and decision-making.
"Players chasing high kicks have to make better decisions, run the proper arc and get in a position where they can see the player coming down and the flight of the ball and make a decision. It is about better technique, the same as tackling.