Ryan Clark has said that NFL players know that they can avoid failing drugs tests to detect marijuana use.
The Pittsburgh Steelers safety has backed New York Jets cornerback Antonio Cromartie's calls for the drug to be taken off the league's banned substance list.
The 34-year-old, who has denied using marijuana himself, told ESPN: "It's 100% true. They're fighting a losing battle. The testing isn't stringent.
"There is one random test during OTAs and minicamps during the off-season, and everybody will be tested early in training camp. After that, there are no more tests. So guys understand the ways to get around failing a drug test."
NFL commissioner Roger Goodell recently confirmed that the league is looking into the medicinal benefits of the substance.
