As the Baltimore Ravens and other teams in the National Football League open their preseason training camps, the league is issuing a candid heads-up on the dangers of concussions. A poster detailing the symptoms of a concussion and spelling out the dangers of "playing through" a head injury will be hung in every NFL locker room this season. Labeled a "must read," it urges players to promptly seek out the team trainer or physician if they or one of their teammates experiences confusion, dizziness or any of 15 listed symptoms.

"Work smart. Use your head, don't lead with it," the poster states. It adds "concussions and conditions resulting from repeated brain injury can change your life and your family's life forever."

This is a good call and a change of tactics for the NFL. Until recently, the league was playing defense on concussions, denying that there was a firm link between head injuries and playing football. Now the league has switched to offense, stating the risks of concussions and working on ways to minimize them on the playing field. The locker room warning about head injuries is the work of the league's medical committee and was written in cooperation with the players union and the Centers for Disease Control and Prevention.

Part of the league's new stance toward preventing head injuries includes testing equipment. Sixteen types of football helmets recently passed laboratory tests simulating the forces of open-field collisions, with three — the Riddell Revolution, the Revolution Speed and the Schutt DNA Pro — singled out as the top performers. A committee of league and union representatives is also looking at practice regimens. There is some thought that repeated blows to the head delivered in weekday practice sessions increase the likelihood of concussions. However, getting professional coaches, who depend on winning for their livelihood, to cut back on practices could be a tough sell.

Ravens center Matt Birk has called the forthright statement about concussions a good start but noted that old habits die hard and that some players would probably still try to play through head injuries. Another Raven, cornerback Domonique Foxworth, observed that candid talk about concussions among the pros would also be heard by the legions of amateurs who love to play football.

Already, awareness of the dangers of playing with concussions has been addressed by the National Federation of State High School Associations. This national leadership organization for high school sports has mandated that, starting this football season, any player who shows symptoms or behaviors associated with a concussion must be removed from the game and cannot return until cleared by an appropriate health care professional. The Maryland Public Secondary Schools Athletic Association is encouraging its coaches to take a free, 20-minute online course, "Concussions in Sports — What You Need to Know." It provides a guide to recognizing and managing concussions in high school athletes.

Football is the No. 1 participatory sport for American boys at the high school level, with some 1.1 million of them playing last season. In a few weeks, high school teams will start their preseason training, emulating in some ways the hard, hot drills that pros go through.

Ravens head coach John Harbaugh has said that training camp is when the foundation of a football team is laid. It is good to see that part of that foundation, at every level of the game, will now be straight talk about concussions.