Presented By Ravens

Everyone knows former NFL running back Ricky Williams used marijuana during his career. He tested positive for the drug four times, contributing to a year-long suspension in 2006.

Now he's claiming that the majority of NFL players and some coaches use marijuana, too. 

In an interview with Sports Illustrated, Williams said he played with quarterbacks and under coaches that smoked pot, and estimated a full 60 to 70 percent of NFL players doas well. 

How do that many people use a banned substance without being caught? Because most players are only tested for "substances of abuse" once per year before the season begins. They know when to expect testing and stop using in that period. 

That schedule becomes more frequent for those who've tested postive. Williams estimates that he was drug tested roughly 500 times -- so often that his wife became friendly with the testers. 

Williams, who retired for good in 2012 after one season with the Ravens, said players turn to cannabis for pain management as an alternative to traditional painkillers, especially the addictive opiod-class drugs. 

He agrees with former Raven Eugene Monroe's belief that the NFL should explore the theurpeutic benefits of marijuana.

Monroe remains a free agent after being released by Baltimore in June, leading to speculation that his vocal marijuana advocacy has hampered his job prospects.