7. Dominic Ryan
The Ireland international retired at 28 earlier this month from “terrifying” concussion related health problems..
Speaking in the Irish Times, Ryan said: “It’s a weight off my shoulders…with a bit of distance I can see it was a no-brainer to retire. I can see now I was literally putting myself in harm’s way.”
8. Nic Berry
Despite suffering numerous head injuries in recent seasons, the 28-year-old Australian was cleared to start the 2012 campaign for Wasps.
But a “concussive episode” during the season opener against Harlequins has forced him to quit the game after two years at Adams Park.