The only NFL player to openly advocate for medical marijuana has donated $80,000 to fund cannabis research on football players at the University of Pennsylvania and Johns Hopkins University.

Eugene Monroe, an offensive tackle for the Baltimore Ravens, previously urged the NFL to remove marijuana from its banned-substances list so players can use it to treat chronic pain.

"As a player, I'm not allowed to use cannabis, but I've been prescribed opioids for various injuries," Monroe said Thursday evening. "The opioids work, but they're very dangerous and highly addictive."

Monroe, a New Jersey native, said he has watched as teammates and friends battled with addiction to opioid painkillers.

At Penn, three research projects are investigating the therapeutic use of cannabinoids, chemical compounds derived from hemp and marijuana. Two are examining cannabis as a treatment for post-traumatic stress disorder in veterans. The third is testing cannabis oil to reduce seizures in children with hard-to-control types of epilepsy.

Monroe's donation - routed through Realm of Caring, a Colorado-based nonprofit - will spur investigations into marijuana's effects on pain and brain injuries in football players.

"We're doing two studies to start," researcher Marcel Bonn-Miller of Penn's Perelman School of Medicine said Friday. "We'll be examining both current and retired NFL players to understand the impact of cannabis or cannabinoid use on recovering from injury."

Studies have found "moderate" evidence that the cannabinoid THC can be effective for treating neuropathic pain. A recent clinical trial in Israel involving 176 chronic pain patients found cannabinoids provided long-term improvement in pain scores and a significant reduction in the use of opioids.

"Opioids are ruining lives across the country, and as athletes we're not immune to those perils," said Monroe, who has been prescribed prescription painkillers as he recovers from shoulder surgery.

Monroe's career as a Raven is uncertain. Though he has three years left on his five-year contract, the left tackle has missed 16 games during the last two seasons.

As long as he's on the roster, Monroe said, he'll continue to press the NFL to revise its policies.

"This is an issue that goes beyond any personal career implications. I understand why other players may be adverse to speaking out, but our health is worth it."

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