Stem cells can help repair damaged bodily tissue, although it is a relatively new form of treatment.

Sanderson expects Curry to be back available around Christmas, and says he sought input from England head coach Steve Borthwick when mapping out how to manage the player for the rest of the campaign.

"We put a little bit of a plan together, of which the stem-cell procedure is a part of it, then looked at the rest of the season," Sanderson said.

"Steve Borthwick looked [at the plan] and is 100% behind it. We want to get him to the World Cup without having another operation."

An England player has a 30-game season limit, but given Curry's injury history and his robust style of play, Sanderson says he won't look to push him anyway near that maximum.

"He'll feature in around 23 games, and 16 of those will be for us," he added.

"And the rest internationals. So we have figured all that out so we don't push him to that 30-game max.

"The consideration is he has a chronic injury which he is managing really well, but the more he plays the less shelf-life he has.

"We generally go by the principle it's going to be three games on one off, or two on one off. I don't think it's wise [to push his game number to 30]."

Curry started England's autumn matches with New Zealand and Australia, but was knocked unconscious against the Wallabies, meaning he was unavailable for the visit of world champions South Africa.

However he returned to start the victory over Japan, a selection that was widely questioned.