The NHL has a serious headache right now. Concussions have always been a problem is the sport, but they have been a particular issue this year.

The list of players out of action with concussions would be a heck of an all-star team.

Sidney Crosby, the best player on the planet, missed much of last year, returned with a bang this year, but is out again as the symptoms have returned.

Chris Pronger, one of the best defensemen in the league, is out for the year in Philadelphia.

Claude Giroux of the Flyers was leading the league in scoring before he missed two weeks with a concussion.

Ottawa’s leading scorer Milan Michalek took over the scoring lead from Giroux then fell to a concussion of his own.

Last year’s rookie of the year Jeff Skinner is out.

New York Rangers top defenseman Marc Staal has been out since a hit from his brother Eric last February.

Brad Richards, the splashy acquisition of the Kings this offseason, is out.

Joni Pitkanen, Brian Rolston, Kris Letang — the list goes on and on.

As of last Friday there were 23 players officially out with concussions, and several others suspected of having them even though they weren’t listed on the injury report. It’s a serious, serious issue.

So, why has this become such a problem right now? There is a long list of contributing factors, but four really stand out in my eyes.

First, players are bigger and faster thanks to nutrition and conditioning programs that are a dramatic step forward from what players used to follow.

Second, shoulder and elbow pads are bigger and harder than ever — like a suit of armor — so heads are getting hit with more force.

Third, rules changes in the league that have severely limited contact have opened up the ice and let players travel with more speed. That means more momentum behind hits.

Finally, as awareness has grown more players are admitting that they have concussions, and teams are getting much better at recognizing them, dealing with them, and keeping players out of the lineup until they are ready.

While the priority has to be on the league and the pursuit of ways to deal with this problem, it’s also important to recognize that this issue has a big impact on NHL handicappers. The look and feel of the league has been affected by this situation, and the impact will only be more intense as the media attention and public scrutiny grows.

Here are three factors to keep in mind when considering how the epidemic of concussions impacts bettors:

Crucial to look at real impact

It can be easy to panic when a player is lost to a concussion — especially because there is a good chance that the player will be lost for quite a while.

It’s very important to not let emotion or hype carry you away in your betting decisions, though. Instead, you need to focus on the real impact of the injury to the team.

Crosby is better than anyone, so his loss is huge. Still, the team had a strong second half of the season last year, and they have the third most points in the Eastern Conference this year and are on track to be a serious contender when the playoffs roll around with or without Crosby.

The Flyers have gone 10-4 with Pronger out of action even though he is as good as any defenseman in the league.

Both of these teams have managed to endure losses that would have crippled other teams because they are deep, talented and well-managed squads. If you had panicked after either injury — like many bettors surely did — then you would have been throwing away money.

Can’t get too excited about return

When a player returns from a concussion he has probably been out of action for quite a while, and he hasn’t been able to work out at full capacity or practice with contact for much of that time. That means he is going to be rusty when he returns, and his fitness is going to be less than optimal. He’s also likely to be tentative until he gets a sense of what he can handle and how his body reacts.

A return to action isn’t an instant cure for a team, then, so it is important to be conservative in your evaluation of the impact of the return until you know what you can really expect from the player.

Enforcement will heighten

The NHL is a very reactionary league. When they have a problem they take strong action to try to remedy those issues. That’s why every year there are major rule changes, and why the game we see now looks nothing like the game of 10 or 20 years ago.

As the pressure to address this issue intensifies, you can expect the league to take some drastic actions. They already have with things like their strong reaction to head shots and other injury-causing hits.

As the league takes steps to deal with this it will be important for bettors to stay on top of what they do and what impact it will have. The betting public will be very slow to really understand what a change means, so smart bettors can have a nice period of profit if they are on top of it.