The French doctor who suggested Jonathan Sexton had suffered up to 30 concussions in his rugby career has apologised to the Irish captain.

Dr Jean-Francois Chermann made the claim to French radio station RMC yesterday in the wake of Sexton being replaced during Ireland's Six Nations defeat to Wales in Cardiff.

Sexton, currently undergoing the return-to-play protocols ahead of Sunday's match against France, said today that he was "saddened and shocked" by the comments from the doctor who recommended he take a 12-week breaking from playing while with Racing Metro in 2014.

In a follow-up statement to RMC today, neurosurgeon Chermann said: "Regarding my interview on Sexton, I did not want to talk about 30 concussions, but concussions and sub-concussions (briefly seeing stars).

"And if you ask most rugby players, they will tell you that they have also suffered numerous concussions in their career, which moreover are hardly ever declared.

"As regards Sexton, we cannot say for certain that he has had 30 concussions. I should never have cited this figure without any explanation and I regret the wrong I have done to the player who was my patient and who I respect more than anyone.

"In my neurological experience of treating more than 1500 athletes who have suffered concussion, the pivotal elements ruling out a return to action are: the fact of having suffered concussions close together in terms of time, that a previous concussion has taken time to be shaken off (several weeks) and the fact that the player is under 20 years old because there exists a serious risk of suffering an after shock.

"To be clear if Sexton has not suffered from a concussion for a year, that he is asymptomatic after 48 hours, that the tests carried out are good and that the return-to-play protocol has been carried out properly, then there is nothing to stop him from playing against France."