Some hockey and football teams, NASCAR, and European soccer and rugby clubs also use that test to better determine the severity of brain injuries in athletes. Major League Baseball umpires now undergo brain testing before each season, and Matheny is determined to help bring such testing to baseball.

But that will require some change in what Varitek calls the "cowboy mentality" among major league catchers.

Trainers Davis and Conte both say they have hesitated to run onto the field to check on catchers, knowing that might bring teasing from teammates. Trainers have to balance the macho nature of catching with their concern for a player's health.

"Catching is a very dangerous job," Davis said. "You've got to take your hat off to a guy who wants to do this for a living. It's a tough way to go."

As for Matheny, his future remains clouded. He announced Aug. 3 that he was done for the season.

Before making a decision on 2007, doctors would like to see him fully functional within nine months. If not, returning probably won't even be an option. He wouldn't be cleared medically to compete.

That leaves the Giants in a touchy spot, because Matheny is signed through next season and the club might not know his status until after spring training starts.

Last month, the team had another scare: Triple-A catcher Guillermo Rodriguez went down with a concussion on a foul tip.

Matheny has told general manager Brian Sabean he understands the team must move forward with plans for next year, with or without him. He also realizes that he's more susceptible to further damage if he were to be hit again — a fact of which his wife and five children are also well aware.

Other catchers say they welcome steps to learn more about concussions.

"I think baseball has become a little bit more hip to it," Varitek said. "Trainers are more hands-on and teams aren't as apt to run their guys out there for 130 or 140 games.

"Perceptions are changing, and that's important," he said. "Ultimately it's not about baseball, it's about life."