McAvoy is married to Sullivan’s daughter Kiley, who recently gave birth to the couple’s first child. McAvoy plays defense for the Boston Bruins, Sullivan coaches the Pittsburgh Penguins and their careers had not overlapped until now, when they’re on the same team with the United States at the 4 Nations Face-Off.

These fall into the category of friendly fire delivered in the friendly confines of the locker room.

Pittsburgh Penguins head coach Mike Sullivan is finally getting his chance to coach at the highest level of USA Hockey, as his team will take on Finland Thursday night to open its bid at the 4 Nations Face-off in Montreal. But for Sullivan, it's not just an international tournament, however large-scale that is. For him, it's a bit more personal.

Charlie McAvoy and Mike Sullivan have a strong connection off the ice that goes way beyond hockey. McAvoy is married to Sullivan’s daughter Kiley, who recently gave birth to the couple’s first child.