It seems every time I come to the States lately the major sporting conversation centres on concussion.
Overnight, a starting defender with the Kansa City Chiefs, Jevon Belcher, shot and killed his girlfriend before taking his own life in a car park at the team's home ground, Arrowhead Stadium.
When he pulled the trigger, Belcher was talking with the Chiefs head coach and general manager.
Early reports suggest Belcher may have shot himself in the head, which isn't the way NFL players have been shooting themselves in recent times.
Stars like Junior Seau and Dave Duerson chose to kill themselves with a bullet to the chest so as to leave their brains pristine for the autopsy.
If, somehow, Belcher's shocking actions can be linked to concussion and resultant brain damage, a massive class action instigated against the NFL by thousands of former players will take a giant step forward.
Further muddying these same waters is the case of San Francisco's Alex Smith. Smith, a very able and effective quarterback, had guided his team to Super Bowl favouritism before sustaining concussion three weeks ago.
In that time, his replacement Colin Kaepernick has astounded many observers by becoming San Francisco's first choice quarterback. The speed of change was enough to make the unhappy Smith's head spin even more quickly!
More to the point, it sends a dark message reverberating around the NFL.
In a sport that pays stars like Alex Smith many millions of dollars, where does this leave the competition's most thorny issue?
What incentive is there for players to report and seek out help for head injuries?