Howard Daniel of the Denver Coroner's Office said an autopsy conducted Sunday could not determine the cause of death, adding that additional tests should take between three and six weeks. A massive heart attack is the usual cause of a fatal collapse, according to medical experts, but heart damage of that type is usually readily apparent during autopsy.
Herrion's agent, Fred Lyles, said 49ers team officials told him and Herrion's family that he likely died of a heart attack, which is consistent with medical experience. (Late Sunday, Herrion's brother, Love Savior, denied that the 49ers organization had suggested a cause of death to the family).
"Without any other information, it sounds like he had a cardiac event of some kind," said Dr. Jim Walker, sports science director at The
Orthopedic Specialty Hospital in Murray. "I hate to speculate, but he was a big kid and at this time of year these things happen. Heat and lack of hydration are things that go into producing cardio stresses."
Herrion, whose collapse in the San Francisco locker room came moments after the game's conclusion, was on the field for the 49ers' final 14-play, 91-yard touchdown drive.
He was upbeat coming off the field.
"It's kind of tough right now," said San Francisco defensive back Dwaine Carpenter. "Emotionally, everybody is down.
"From the beginning, he didn't look too good. It looked like he was having a seizure, and then he didn't move at all anymore. He just laid there. When he walked off the field, he was laughing. He was smiling and laughing."
Herrion was given cardiopulmonary resuscitation and was taken to St. Anthony's Central Hospital in Denver, where he died at 11:18 p.m. It is the first on-field death for the NFL since Minnesota offensive lineman Korey Stringer died of heatstroke during a training camp practice four years ago.
Walker said many congenital heart defects aren't exposed until being subjected to the pressure and stresses of athletics.
"It's amazing how agile and fast those guys at that size really are," he said. "But it is a health risk to be that size, athlete or not. You have to supply blood and oxygen to the mass you carry around. The heart is the same size as a guy who weighs 150. The heart is a very limited delivery system. It was not designed to handle the stress and heat."
"He was about 310 when he played here," said Bill Bean, the University of Utah's director of sports medicine. "He was big, but you have to be to play the offensive line. He never had any health problems, no weight issues. Nothing abnormal.
"The NFL has a lot of money tied to these guys. You can bet they turn over every rock to find health issues. Once they think a player is going to be drafted, they do their homework."
Bean said that athletes attending Utah go through several physical exams as well as hydration and supplement issues.
Lyles said the player has weighed as much as 335 to 340 pounds but that he passed physicals with the Dallas Cowboys twice, NFL Europe once and the 49ers twice.
"If something like a heart problem exists, it wasn't detected," he said. "This is a guy that has played football for a long time."
Travis Fox, the offensive coordinator at Kilgore College where Herrion played before coming to Utah, said his players completed intense conditioning drills in 97-degree temperatures and Herrion never struggled to keep pace. He said Herrion never had any injuries or health problems when he played at Kilgore.
''He was healthy,'' Fox said. ''That's why I'm in shock. The young man was in shape.''
Herrion is the second professional football player to die this year. In April, Arena Football League player Al Lucas of the Los Angeles Avengers died of a spinal-cord injury after making a tackle.
''We have done everything medically we could do,'' NFL Players Association President Gene 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.''
Upshaw said that physicals are not a catch-all. New England Patriots linebacker Tedy Bruschi had a stroke on Feb. 16, 10 days after beating Philadelphia in the Super Bowl.
''He had a hole in his heart and might have played with it for years," Upshaw said. "No one ever noticed it.''
Bean had nothing but praise for Herrion the human being.
"I have to say he was something special," Bean said. "He was from Texas, and when he first came here, he was very polite. I thought it would wear off, but it never did. It was always 'please' and 'thank you.' I would tell him to call me Bill, and he never did. My kids really loved him. I never saw him in poor humor."
Some information in this story came from The Denver Post, The Associated Press and from reporters based in California who worked with The Tribune in producing this report.
