Former NFL quarterback Mark Brunell has said that the league needs to crack down on players who use marijuana.

Commissioner Roger Goodell recently said that the NFL would look into the medicinal benefits of the substance, while New York Jets cornerback Antonio Cromartie has called on the league to end its ban on the drug.

Brunell, who now works as an ESPN analyst, told the network: "I believe it's harmful. I believe it has a negative effect on not only NFL players but anybody that does it. Testing should be increased.

"I think if you're going to test for marijuana, it needs to be random, it needs to be often. It has to be stricter, just like the performance-enhancing drug testing is going to be strict."

Pittsburgh Steelers safety Ryan Clark believes that players know how to avoid failing tests when using marijuana.