Catching is an invitation to extinction. Every baseball player feels the gradual dilution of his skills each year but only the catcher deliberately invites decay, like a man who leaves high-grade iron in the rain to rust.

Every baseball player's most abiding fear is the thought of "losing it" -- turning an unseen corner after which it is impossible to go back to what once seemed a routine brilliance. But, among ballplayers, only the catcher seems to deliberately hurry the coming of that awful day. For every game spent crouching behind home plate, it is said, the man inside the tools of ignorance subtracts a day from his career. Perhaps only the NFL running back has a job description that seems so consciously aimed toward self-obsolescence.

Every catcher reaches a crisis point -- a crisis point of conscience -- when he must weigh his considerable value to his team against his own pain and his own future. Two of the game's finest receivers, Carlton Fisk and Johnny Bench, men who just five years ago, when they met in the '75 World Series, looked like young and indestructable prototypes of baseball's toughest position, have reached that depressing crossroad.

Each has made a drastic decision. Bench has told his Cincinnati Reds that, henceforth, he will catch no more than two games a week. The club has agreed, even writing the clause into his contract. It sounds like a proviso for an aged man. Yet Bench is 32. He says simply, "I want to be able to walk when I'm 50." Fisk, because his Red Sox have rejected his pleas along the same lines, has vowed to himself that, come what may, he's never again going behind the plate more than 120 times a season.

Some baseball players lose it, but catchers just throw it away.

Fisk calls catching "the Dorian Gray position, because even though you may look young on the outside, you know that on the inside you're aging fast. Like the 'Portrait of Dorian Gray', you're afraid that one day you'll take off the equipment and discover you've turned to dust."

"A catcher and his body are like the outlaw and his horse," says Bench, "he's gotta ride that nag 'til it drops."

Few catchers have ever ridden their nags harder than Fisk and Bench. In a 10-year span ending in '77, Bench played in 1,513 games -- 1,393 of them at catcher. In '78, Fisk caught 157 games -- the most ever.

"At the end of '78, I was just totally decimated," says Fisk. "I felt like a piece of cooked spaghetti. In the mornings, I could barely walk from bed to the bathroom. I wasn't able to sleep well at night because I was playing with a cracked rib. It was just mental and physical agony. Every time I threw to second base it felt like my arm was coming off from a chronic elbow injury).

"But each day you'd get to the park, and we were in a pennant race, so you'd say, 'We're here. I can strap it on one more day.' I started the year at 218 pounds, and I was in good shape. The last week in October, I weighed 184 -- the least since I was a sophomore in high school.

"What you can't measure," says Fisk, "is what I call the 'deferred payment' effect. Each year you're taking a toll in future years. And you don't know how much."

"Pain is just something that a catcher lives with," says Bench. "I've done that all my life, acclimated myself to it. Once, they X-rayed my foot. The place I had hurt was fine, but they found three old breaks that I'd never noticed."

Bench has had shoulder surgery, long surgery for removal of a nonmalignant growth and a variety of broken bones. Two years ago, a combination of pulled back muscles, back spasms and total fatigue put him in a hospital twice in midseason. An orthopedic corset has long been hung in his locker next to his shin guards and mask.

Fisk worries that a man may go beyond merely acclimating himself to such daily torments. "The amount of pain, the sharpness of it, and the mental strain of thinking about it -- well, it seems like you can endure more each year. Your tolerance increases. Each injury immunizes your mind," says Fisk, who has spent two-month chunks of time on the disabled list in three seasons. "I hate to admit it, but it's almost a relief when you have a real injury and it's impossible to play. In May, I fouled a ball off my instep but stayed in the game. After the game, on the bus, I couldn't even put my shoe on. It was kinda nice. I didn't have to make that decision of whether to play. It was impossible. But even so, I couldn't bring myself to let it heal right. It still hurts and I still wear a sponge in my shoe right now -- four months later.

"The end result is that you lose your ability to discriminate between degrees of discomfort. If your elbow hasn't blown up or you can get down in a crouch, you get conditioned to thinking that means it's all right to play. You don't think about the blood in the joints or the squished ligaments or the floating bone chips. So what if you're bleeding like a pig inside? If you haven't got something big and visible wrong with you, you're expected to play.

"A smarter man might not do that. But I don't think you'd find that he was viewed too highly by his peers."

The irony of both Bench's and Fisk's careers, is that they are such fine hitters they could demand a switch to another position. Yet each year they remain catchers although statistics show, especially in Bench's case, that each game caught robs them of batting punch.

"You have to know the game to understand why a catcher feels so special about his work," says Fisk. "And I call it work. Baseball has never been pleasure to me from the first day. Behind the plate, you have every part of the game running through your fingers. Everything you do, every pitch you call or throw you make or bunt you field, affects the game. Whether it's running the bases, batting, or just moving a defensive player, you're involved in everything. You touch the total game. Nobody else does."

To try to measure all the tiny ways in which dedicated catchers mean victory, Fisk and a coach kept records in '77 and '78 of every pitch in the dirt that Fisk blocked and how many runs they eventually kept from scoring. "We called it 'BBRRS: Balls Blocked Resulting in Runs Scored.' Something like that," says Fisk. "In '77, it was 64 runs. In '78 it was '71."

If fans don't know, management does. Folks in Cincinnati and Boston have dragged their feet in every conceivable way to keep Bench and Fisk in their irons. Finally, when it came time to renegotiate, Bench simply gave an ultimatum. He would play 120 to 130 games a year, but only those two a week behind the plate. Since he has 24 homers in fewer than 400 at bats this year while working under the catching strain, he may yet again become a 35-homer man. There are even rumors he will be traded to an American League team next year, a DH heaven. But any real baseball man knows that Bench with 18 homers, but 140 games at catcher, will win more Cincy games than 36 Bench homers and only 50 games caught.

Bench, however, knows that, unless he wants to end up hating his game, he is making the only possible choice. For a long time, he has teased Tom Seaver, saying, "You know shy I envy you? Cause you pitchers only have to bear down and really play baseball 40 times a year. No wonder you think it so much fun."

"I'd like to follow a program like Bench's says Fisk, "but maybe catch 100 games. Just missing the day games after night games would make a huge difference. But the manager looks at the statistics and I can understand why he can't go along."

The '80 statistics say that Boston is nearly 30 games over .500 when Fisk catches, and nearly 20 games under .500 when he doesn't. By luck, Fisk has been injured often enough this year that he says, "I actually feel human."

Nevertheless, the tools of ignorance have a strong magnetic force over even the brightest of men. Last Sunday in New York, Fisk had the flu. "I was up for five hours throwing up," he says, "and I had one hour's sleep. I had caught the night before. I came to the ballpark feeling dead. Sore stomach, aching all over, and my right eye felt like it was going to blow out of my head. A drunk would have been in better shape to play. But I knew that the only way I wouldn't be in the lineup was if I went to the manager and said, 'I just can't play.'

"I had this tremendous guilt feeling. Maybe it's just insecurity. You always doubt whether you're in a position to make demands of management. It's an old ingrained response that you probably learn in the minors -- like in my case I made the majors strictly on defense. I never hit a lick in the minors. You're always thinking, 'Jeez, I got here by catching. What if I tell 'em I can't catch? You never completely get rid of that feeling that "I'm a guy from a little New Hampshire town of 1,200, one of six kids, had a paper route for 32 cents a week and now I'm playing for the Boston Red Sox.' That's ridiculous, but deep down, it must be part of you.

"It's hard to realize what you're doing to yourself. Every ballplayer thinks he can still do all the things he did five years ago."

For other ballplayers, those five-year increments may apply. But for many catchers, that is a whole career. For the best, like Bench and Fisk 10 or 12 years is an eternity.

They are ready now, much as it dismays them, to loose their hold on their game, stop sifting every pitch and play through their fingers. It was a painful decision for each. But not nearly as painful as the alternative.