Headbutt player: Serious. Headbutt spouse: Not much.

Maybe we shouldn't expect tough, harsh punishment from the National Football League when the actual justice system isn't much better. Or any better.

On Thursday the Arizona Cardinals running back Jonathan Dwyer pled guilty to misdemeanor disorderly conduct and was sentenced to 18 months' probation.

Apparently, there also is some community service.

As you may recall, 25-year-old Dwyer was arrested in September after it was alleged that he broke his wife's nose during an altercation.

According to reports, Dwyer was trying to kiss and undress his wife, who wasn't in the mood and bit his lip. Police said that Dwyer then broke his wife's nose when he head-butted her.

On the playing field that would draw a 15-yard unsportsmanlike conduct penalty and perhaps even an ejection.

A player might also be fined and suspended.

The penalties aren't much different in real life.

Except Dwyer's wife wasn't wearing helmet. And the confrontation was no game.

Dwyer was indicted on a single account of aggravated assault and eight misdemeanors including criminal damage and disorderly conduct.

The Cardinals put him on the reserve/non-football injury list but, according to reports, continued to pay his salary. He's now a free agent (though facing a six-game suspension.)

There were also reports of other altercations between Dwyer and his wife, one even involving their 17-month-old son, but no other charges were filed.

During this year's Super Bowl the NFL will air a public service announcement meant to address the issue of domestic violence.

That's a good thing.

Domestic violence is a problem for the NFL. It's a problem for all of us.

And maybe it's not unusual for a regular guy to receive probation after having been accused of the same offenses that Dwyer was accused of committing.

But it's pretty clear that what most separates Dwyer from running back Ray Rice is, simply, video tape.

There's no moving pictures of Dwyer head-butting his spouse.

Imagine if there were.

If there had been a video showing such a thing do you suppose his case would have flown under the radar, as it seems to have done, on Super Bowl week?

Particularly on a Super Bowl week when the NFL is giving up multi-million dollar advertising time to demonstrate its concern for domestic violence?

How tragic is that?

One of the very worst part of domestic violence is that so much of it happens behind closed doors.

In the end, could there be a worse example of … out of sight, out of mind?