Tank Johnson (David Trotman-Wilkins/AP/Chicago Tribune)

Perhaps, NFL players just need something to take the edge off after getting slammed by 300-pound human torpedoes all day, or maybe it’s that a good deal of them are still going through their experimental phases in their 20s. Whatever the case, it’s no secret that at least some football players use marijuana. Some get caught, such as Cardinals defensive tackle Daryl Washington, who was suspended today for an incident involving marijuana.

But Washington isn’t in the minority, according to veteran defensive tackle Terry “Tank” Johnson. The ex-Chicago Bear estimates to Fusion TV that “70 to 80 percent” of NFL players use marijuana. “I hate to say that as if it’s a bad thing, but I think that would be about accurate.”

As to why players use the illegal substance knowing full well the consequences of getting caught violating the NFL’s drug policy, Tank said, “It’s a good way to relax and enjoy yourself and have a good time, so I think that’s why guys gravitate toward the green.”

Um… Seeing as though there are quite a few, more legal ways to have a good time that don’t result in suspensions or fines, that seems like a pretty poor excuse. The Fusion report, which seems to skew toward the pro-legalization lobby, offers an alternative explanation for the possible widespread use of pot — self-medication.

“Managing and tolerating your pain is how you make your money in this game,” Johnson said, who added he’s broken multiple bones, suffered “a few concussions here and there” and experienced various other types of pain on the job.

Although Fusion’s report is based on the anecdotes of Johnson and a couple of other football players, it is likely that at least some players probably prefer to manage their pain through marijuana. It could be that they prefer “the green” to more traditional prescription pain medications, which have come under fire in the NFL for misuse. Recently, a group of former players filed suit against the NFL, alleging the league advocated them to use prescription pain medications without disclosing the risks of addiction.

ESPN.com columnist Gregg Easterbrook writes about the problem of prescription drugs in his new book “The King of Sports: Football’s Impact on America,” as well:

“Just as head trauma is coming into the light of day as a football problem, so is painkiller abuse. Professional football players are major consumers of three kinds of painkillers: Narcotic pills such as Vicodin, injected local anesthesia, and Toradol, an all-purpose pain reliever that a disturbing number of NFL players have injected even when they are feeling fine.”

With that in mind, it’s logical to ask whether using marijuana for medical reasons should be allowed in the NFL. That’s a sticky question as surely some players, as insinuated by Johnson, would continue to use it purely for recreational purposes, with or without a prescription. Ergo, if someone were to test positive, it’d be hard to know whether to cite him for a violation or not.

As for NFL Commissioner Roger Goodell’s view on medical marijuana, he has said he would considering allowing it. Goodell told USA Today:

“I’m not a medical expert. We will obviously follow signs. We will follow medicine and if they determine this could be a proper usage in any context, we will consider that.” At the moment, though, he added, “our medical experts are not saying that.”

In other words, nothing will change regarding the NFL’s drug policy anytime soon. It seems for now, if Johnson’s estimate is correct, those 70 percent to 80 percent of marijuana users in the NFL might want to think twice before their next puff, no matter the reason.