Mark Messier was all hard edges when he was the star of the National Hockey League, strong, rough-hewn, and looking all but invincible.
But the man who captained both the Edmonton Oilers and the New York Rangers to Stanley Cups had his points of vulnerability. He was "devastated" by concussions that ended the careers of teammates Mike Richter and Jeff Beukeboom.
"Mike Richter had small children but couldn't even pick up his own baby for the longest time without feeling dizziness and nausea. Jeff suffered depressions," Messier told The Globe and Mail this week.
"When you see close friends of yours hurt to that degree, you wonder what could have been done. Mike Richter still can't lift any weights. If he gets his heart rate up, he feels sick."
The NHL legend is doing something about the issue, piloting a helmet project for a Cascade Sports - a U.S.-based sports equipment manufacturer with a new technology which the company claims will reduce the possibility of concussions.
Messier will join globesports.com on Monday afternoon to talk about the concussion problem plaguing hockey players of all ages and skill levels.
Send the Hall of Famer your questions on the issue using the Comments function on this story. We'll cull the best of them, and provide his answers Monday on globesports.com.