Ravens left tackle Eugene Monroe has missed nearly half the team's games over the past two seasons, battling knee and ankle injuries in 2014, the concussion he sustained in the opening game of 2015 and the shoulder injury that ended his season.
To deal with the pain, the seven-year veteran would like to use medical marijuana, which has been legal in Maryland since 2014.
But because it's on the National Football League's list of banned substances, he would face a suspension if he tried.
It's out of frustration, Monroe says, that he has unleashed a barrage of tweets in support of the drug, breaking a silence among active players on the subject.
Monroe, 28, called on the NFL to support research into medical marijuana, tore into NFL Commissioner Roger Goodell, and encouraged fellow players to "stand up" for a cause he says won't benefit only them but individuals in all walks of life.
The tweets, including 37 posted in one two-hour span on Tuesday, ranged from angry to idealistic — a mix Monroe said "has gotten a lot of reaction."
"We all love the game!" he wrote in one tweet. "Let's do some research to protect the players who make it great." Then he challenged other players to donate to research.
"The reaction I'm getting from players is very positive," he told The Baltimore Sun during a break from training at the Ravens' practice complex this week.
"It has been very positive from non-players, too."
He said he had been contacted by "families who have had their very sick loved ones healed by doctor-prescribed CBD," or cannabidiol, a chemical in the cannabis plant that is used for medicinal purposes.
"They've told me it was their last option, and it has actually changed their lives," he said. "What I'm talking about is something that can be very beneficial to a lot of people, not just athletes."
The comments by Monroe — who first spoke on medical marijuana in an interview with CNN last week — come as the NFL has acknowledged for the first time a link between football-related brain injuries and chronic traumatic encephalopathy, or CTE.
Jeff Miller, the league's senior vice president for health and safety, spoke of the link on Monday before the House Committee on Energy and Commerce.
Twenty-three states and the District of Columbia have legalized the use of medical marijuana, and 17states regulate oils derivedfrom marijuana plants. But the NFL, the National Basketball Association and Major League Baseball bar players from using the drug for any purpose.
All offer treatment for players who test positive for marijuana for the first time. But they also hold out the possibility of suspensions for repeat offenders, or for those who fail to follow their treatment plans.
The National Hockey League does not list the drug as a banned substance, but it monitors use through testing. Individual teams may discipline users according to applicable state or provincial laws.
Goodell addressed his league's policy, which both the NFL and the players' union approved in their current collective bargaining agreement, during Super Bowl Week.
"It's an NFL policy [to ban all cannabis use] and we believe it's the correct policy, for now, in the best interest of our players and the long-term health of our players," he said.
Goodell said science has advanced understanding of how marijuana can be used medically. But he said it hasn't learned enough to prompt a reversal.
"I agree there has been changes, but not significant enough changes that our medical personnel have changed their view," he said. "Until they do, then I don't expect that we will change our view."
Monroe has ripped Goodell on Twitter.
"It's a shame that Roger Goodell would tell our fans there's no medical vs recreational distinction," he wrote.
"If I'm a fan, I'm [angry] [ticked] at the time I wasted listening to Goodell lie to me at the Super Bowl. As a player I sure am."
Reached for comment, an NFL spokesman reiterated that the league and players worked together to develop the current rules.
"The substances of abuse policy is collectively bargained and is a joint NFL-NFLPA program," said Brian McCarthy, a league vice president for communications. "We are guided by medical advisers. They have not indicated a need to change."
Kevin Byrne, a spokesman for the Ravens, said Monroe's views on the subject "are Eugene's thoughts" and declined to comment further.
The NFL Players Association declined comment.
Monroe, a University of Virginia star who was picked eighth overall in the 2009 NFL draft by the Jacksonville Jaguars, told CNN last week that playing professional football "automatically gives you the symptom of chronic pain."
"You're hitting each other as hard as possible every single day in practice," he said. "Your body is in pain a lot of time."
Monroe acknowledged that other drugs may be used to treat pain, such as opioids But he said players are wary of their addictive properties.
He went further on Twitter.
"Any coach, GM, fan or owner concerned about the player being 'high' should know that they already are, on prescribed opioids," he wrote.
Monroe said anecdotal evidence suggests that medical marijuana might have beneficial effects for those who suffer from CTE.
"I'm not here advocating smoking weed for recreational purposes," he wrote. "However, smoking weed may just protect your brain."
Monroe said he would donate $10,000 to the Realm of Caring Foundation, a 3-year-old nonprofit based in Colorado that works with hospitals, doctors and patients to collect data on cannabis products and to advocate for medical marijuana use.
Dr. Ryan Vandrey, an associate professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, works with the foundation. He helps to gather and interpret information from the more than 5,000 medical marijuana users on its patient registry.
Vandrey, who has worked in the field for 16 years, says the study of medical marijuana use is still in its earliest stages. Most of the research so far has focused on how cannabinoids — chemicals that act on human neuroreceptors — can be used to treat pain or seizure disorders such as multiple sclerosis, Vandrey said.
But he said there are many anecdotal reports of "much broader health benefits."
The foundation is trying to gather those anecdotes, "then use that information to form hypotheses that we can then test in studies," he said.
Vandrey backed Monroe's contention that there's a vast difference between THC, the powerful chemical in cannabis prized by recreational users, and cannabidiol, CBD, the medicinal chemical that scientists have used plant-breeding techniques to intensify.
They're two of the 400 or so unique chemical compounds found in cannabis. Varney said they have very different effects.
"CBD is not psychoactive like THC is," he said. "When administered, it doesn't cause intoxication."
Several retired NFL players have said they used marijuana to treat pain during their careers.
Former Ravens linebacker Brendon Ayanbadejo, joined two other ex-NFL players in January to argue on the Huffington Post that the league "should allocate financial resources to advance medical research on the efficacy of medical marijuana in treating brain injuries."
Jay Williams is one of several retired NBA players who have emerged as advocates.
Williams, a former guard at Duke and with the Chicago Bulls, estimated that 75 percent to 80 percent of NBA players already use marijuana to deal with the stress and physical pains of the long season.
He told Fox Business on Wednesday that marijuana is "something that the whole world is becoming more progressive with. So it's about time some of these [pro sports leagues] do as well."
In 2013, major league pitcher Jeremy Jeffress, then with the Toronto Blue Jays, sought permission to continue using marijuana to ease the effects of epileptic seizures, as he had done for years. He was denied.
Advocates looking to effect change might have to wait until current collective bargaining agreements expire.
For Major League Baseball, that happens this December. For the NBA, it occurs next year. The NFL's doesn't end until 2021.
Monroe says it's too early to gauge the impact of his comments.
He says several fellow players told him they were glad someone finally spoke up. But he hasn't heard from any who pledged to donate.
As far as he's concerned, he says, the case for more research is obvious, and for more than just the men who take to the field on Sundays.
"These are families in our country in grave need of alternatives to our current medical options," he said. "I would hope that anyone who saw my messages, who took a non-biased look at them, will see that [medical marijuana] is something that can benefit all kinds of people.
"It's just common sense to look into it more."
Baltimore Sun reporter Jeff Zriebiec contributed to this article.