"A Must Read for NFL Players," it declares in large letters. "Let's Take Brain Injuries Out of Play."
The poster is the latest step by officials at the NFL's headquarters to persuade players and coaches to take head injuries more seriously than they once did.
Last December, the league tightened rules on when players could return to the field after suffering blows to the head. Players showing any of several symptoms, even if they remain conscious, must be benched for the rest of that day. They also cannot return to practice or play until cleared by the team physician and an independent neurological consultant.
Previously, only players who lost consciousness had to be kept out of action under league rules. A pamphlet given to players for the last three seasons minimized the risks of repeated head injuries.
"Current research with professional athletes has not shown that having more than one or two concussions leads to permanent problems if each injury is treated properly," the pamphlet said. It also suggested that it was unclear whether NFL players could suffer long-term brain damage as a result of head injuries.
In contrast, the poster now being distributed to NFL teams warns in stark terms that head injuries can have lifelong consequences.
It says that practicing or playing while symptoms persist "can prolong the time to recover," and that "playing through a concussion ... may cause permanent damage to your brain."
"According to the CDC, 'traumatic brain injury can cause a wide range of short- or long-term changes affecting thinking, sensation, language, or emotions,'" the poster continues. "These changes may lead to problems with memory and communication, personality changes, as well as depression and the early onset of dementia. Concussions and conditions resulting from repeated brain injury can change your life and your family's life forever."
The poster also shows photographs of children playing sports, with a caption reading, "Work smart. Use your head, don't lead with it. Help make our game safer. Other athletes are watching."
It tells players who think they might have suffered a concussion to report it and seek medical evaluation. Over the earlier objections of the Players Association, it also recommends that players tell the team's medical staff about other players who might have suffered a head injury.
However, the league must overcome a decades-old tradition of playing with injuries, including concussions. In an Associated Press survey of 160 active players last year, 30 said they had hidden or played down the effects of a concussion at some point in their careers.
In March, the league acknowledged that NFL careers can lead to neurological and mental health problems. It set up a new program for retired players, providing coordinated neurological care at five medical centers around the country.