Harlequins have brought in head specialists to asses Mike Brown's concussion-like symptoms, which have seen him miss nearly 12 weeks of action.
The 29-year-old recovered from a collision with Italy's Andrea Masi midway through this year's Six Nations to feature in England's final two games of the tournament, but he has failed to represent his club side since.
Brown, who is said to still experience headaches following the coming-together, was recently ruled out for the remainder of the campaign.
"We had people in today to look and see what the best way forward is for him," Quins director of rugby Conor O'Shea is quoted as saying by The Telegraph.
"It will clear. You have seen instances already this year for players where it just takes time. In the past it would have been rushed because you just didn't have the knowledge we have now.
"I want people to understand that the game is safer because we are looking after players as opposed to the old way of getting on with it for your mate."
Ireland and Racing Metro fly-half Jonathan Sexton also had to miss 12 weeks of action earlier this season as a result of numerous concussions.
