Are head injuries the reason Ben Roethlisberger is such a colossal jerk?

That's the theory floated by Sports Illustrated writer David Epstein, in an interview with neuropsychologist Dr. Jordan Grafman -- Roethlisberger, after all, has suffered four concussions on the football field during his NFL career.

According to Grafman, two particular behaviors are endemic to people with moderate or severe frontal lobe injury, or to people with more mild but repetitive injury: 1) violating social rules by saying inappropriate things, and 2) saying appropriate or typical things in an inappropriate context.

"If you're married and you're flirting with another woman in an elevator with your wife next to you," Grafman says, "that's the kind of clearly inappropriate behavior." Roethlisberger is not married, but one man told me that Roethlisberger had asked out his wife while the man was present.

Granted, as Grafman notes, "we all say inappropriate things sometimes," but "it's the frequency with which it happens, and the unawareness. When you have a frontal lobe injury in particular, you often become unaware of your inappropriate behaviors. The observations usually come from wives or children." A typical situation in my reporting last week was something like this: I would hear that Roethlisberger had, for example, said inappropriate things to waitresses at a restaurant or walked out on a bill, so I would call the establishment. "I don't know if he walked out on a tab here," would be a typical response from whoever picked up the phone, "but he was really rude to my friend after he invited her over to his table." Tales of indecorous acts abounded.

Or it's possible that Roethlisberger is, you know, a colossal jerk. He wouldn't be the first multimillionaire athlete with dangerous delusions of entitlement, would he? Didn't we all kind of hate the jocks in high school?

And yet: If Epstein's onto something here, the morality of the NFL itself gets trickier and trickier to defend. There's already substantial evidence that playing professional football destroys the bodies and minds of the men who play it. If also it transforms them into moral monsters -- as a natural, organic byproduct of the game -- how could you possibly watch another game in good conscience? What redeeming value is left?