The NFL's drug testing program for illicit drugs like marijuana and cocaine might be the best in sports. It's thorough and formidable. Almost everyone I've spoken to says this. There are dissenters but that's the way the policy is generally seen. But there is one potential issue as the arrest of Detroit's Nick Fairley shows.

Fairley was arrested for second-degree marijuana possession. Another Lions player, Mikel Leshoure, was also recently arrested for marijuana possession.

From what I've been told, neither player was in the NFL's testing program for illicit drugs, and this illustrates the only weakness in an otherwise extremely strong program.

If a player is in the testing program, he's tested for drugs like marijuana repeatedly, even in the offseason. Basically, if a player in the program uses, there's a very good chance he'll get busted.

But if a player is not in the testing program, it's different. During the season there are random tests but in the offseason players are given an annual drug screen that is given randomly during a three-month window (May-July) prior to the season.

This is probably why Fairley and Leshoure felt comfortable possessing (allegedly) and presumably using pot. It's early April. Random tests don't start until May and even then they may not get picked for those tests. Marijuana may stay in the system for weeks but my guess is players know something about exactly how long pot does remain in the blood and felt comfortable.

That's the problem. There's a nice-sized window for a player to get his pot on. Or his coke on. Or whatever. And trust me: players are well aware of this window.

There are still risks of course. A player could be arrested (looking at you, Fairley) or maybe that blunt stays in the system longer than expected and they're busted in a test. Still the rules allow a lot of leeway.

And, again, the players know it.