The cause of offensive lineman Thomas Herrion's death cannot be determined until toxicology tests are performed, a process that usually takes three to six weeks, a coroner said Sunday. The 23-year-old offensive guard for the San Francisco 49ers collapsed in the locker room Saturday night, minutes after the team's preseason game against the Broncos on a 65-degree evening in mile-high Denver. He was taken to the hospital and pronounced dead shortly after.