Ryan Clark says NFL players, including some of his teammates with the Pittsburgh Steelers, turn to smoking marijuana for a variety of reasons, especially as a means to relieve pain and manage stress.

Clark, a 12-year veteran, discussed the topic of marijuana use and the league's testing system Thursday morning on ESPN's "First Take."

"I know guys on my team who smoke," Clark said. "And it's not a situation where you think, 'Oh, these are guys trying to be cool.' These are guys who want to do it recreationally.

"A lot of it is stress relief. A lot of it is pain and medication. Guys feel like, 'If I can do this, it keeps me away from maybe Vicodin, it keeps me away from pain prescription drugs and things that guys get addicted to.' Guys look at this as a more natural way to heal themselves, to stress relieve and also to medicate themselves for pain. Guys are still going to do it."

Clark also agreed with recent comments by New York Jets cornerback Antonio Cromartie, who suggested the league is waging a lost cause in banning the substance, while also saying the league's testing system isn't all that effective.

"It's 100 percent true. They're fighting a losing battle. The testing isn't stringent," Clark said. "There is one random test during OTAs and minicamps during the offseason, 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."

Marijuana became a hot-button issue at the Super Bowl, as both teams -- the Seattle Seahawks and Denver Broncos -- hail from states that legalized marijuana. Seahawks coach Pete Carroll created headlines by saying he agreed with the notion the league should investigate medicinal marijuana to see if it can help players. Medicinal marijuana is legal in 20 states, plus the District of Columbia.