Shortly after 300-pound lineman Al Lucas broke his neck during an Arena League game and died in April, Paul Tagliabue and Gene Upshaw sat down to discuss whether anything more could be done to prevent deaths in their game.

The NFL commissioner and the head of the players’ union decided that, at the top level of football, all possible precautions already were in place.

The death of Thomas Herrion, an offensive lineman for the San Francisco 49ers, demonstrates that sometimes, “all” isn’t enough.

Herrion, who collapsed after a game Saturday in Denver, had been on the San Francisco and Dallas practice squads and played in Europe this past spring as he strived to make an NFL roster. At 6-foot-3, 310 pounds, Herrion was average size for his position – perhaps below it in a league where a vast majority of offensive linemen weigh more than 300 pounds.

He had passed stringent physicals just to be allowed to compete for a job, including stress tests. When he collapsed in the locker room after Saturday night’s game, trained medical personnel were there immediately, and he was rushed to a nearby hospital. Three hours later, the team announced he had died.

“We have done everything medically we could do,” Upshaw said Sunday. “We have doctors trained in emergency medicine, in heart problems and other specialties standing by at every game. It’s not just internists. It’s people who know what to do in every emergency. It just wasn’t enough.

“This is the second time this year we’ve lost a player, and that’s two too many.”

But he added that physicals couldn’t catch everything, noting the case of Tedy Bruschi, the New England Patriots linebacker who had a stroke on Feb. 16, 10 days after helping the Patriots win their third Super Bowl in four seasons.

“He had a hole in his heart and might have played with it for years. No one ever noticed it,” Upshaw said.

Since the death of Minnesota offensive tackle Korey Stringer four years ago, the NFL has increased its medical vigilance in training camp.

Many teams, for example, have avoided practicing in the midsummer afternoon heat and many have ended two-a-day practices in pads after coaches began to realize the stress that can place on big bodies – even those in prime condition from year-round workout programs.

It has been common this summer, for example, for teams to work out in the early morning and then not again until the evening on days when they practice twice. Many of them follow those two sessions a day with just one practice the next.

Those kinds of precautions have been the norm since Stringer, a 340-pound Pro Bowl tackle, died of what was later determined to be heatstroke during Vikings camp in 2001.

Even before then, the presence of trained medical personnel has helped save lives.

On Dec. 13, 1997, Detroit linebacker Reggie Brown injured his spinal cord during a game. He stopped breathing on the field, but doctors and paramedics resuscitated him.

Brown was forced to retire from football, but has been able to lead a normal life.