Over a whole career, perhaps no job in sports takes a more brutal toll in daily pain and gnawing physical erosion than being a catcher.

More than 120 men have played 2,000 major league games. None is a catcher.

John Bench, the best ever, stopped squatting for a living at 32. Yogi Berra caught only 100 games after 32. And Bill Dickey, an iron man, cut back his workload by the same age. Gary Carter, 31, already is talking about his not too distant day of decision.

That, in part, is why the Boston Red Sox let Carlton Fisk become a free agent after the 1980 season. He was 33. Owner Haywood Sullivan, a former catcher himself, knew exactly what that meant.

Thursday night in Memorial Stadium, Fisk, now 37, hit his 243rd career home run, moving him past Roy Campanella into third place on the all-time homer list for catchers behind Bench (389) and Berra (313).

That was remarkable, but far more amazing was the fact that, on Friday night, Fisk hit another homer -- his 23rd of the season -- to move into the major league home run lead.

No catcher ever has led the American League in homers. Only Bench (twice) ever led the National League. And he did it at ages 22 and 24.

What Fisk is trying to do is almost impossible at any age, let alone 37.

Needled by a friend that, "You've got no chance to lead the majors in homers," Fisk grinned and answered, "Only because I probably have no chance to play in enough games."

How Fisk is trying to do it is beyond belief.

After all the other Chicago White Sox have left the park, gone home to their beers and their beds, Fisk often still is at the ballpark.

Lifting weights.

Game ends at 10 p.m.

Midnight. Fisk is lifting weights.

At 1 a.m., Fisk is lifting weights.

"Sometimes on the road I don't leave the yard until 1:30 a.m."

When, for some reason -- such as total exhaustion -- he can't lift after games, he's up early the next morning searching for a Nautilus center where he can make himself suffer more.

"He's tough," says manager Tony LaRussa. "He's always been a remarkable physical specimen (6 feet 2, 217 pounds). And he's taken care of himself. But last winter he just worked himself to the bone. He's gone in for weight training whole hog and he's strong as hell. Sometimes over the winter he'd call me from the gym after working out all day and say he was so tired he could hardly get home."

Once, Fisk's nickname was Pudge.

Now, it should be Hulk.

Much about Fisk is paradoxical, tantalizing. On the field, he looks ponderous in his No. 72. Yet he runs on his toes and has stolen 106 bases (a record for catchers), eight this year.

Off the field, away from shin guards and filth, he wears white cotton slacks and pale pastel shirts. He knows Perry Ellis doesn't play for the Twins.

The sign above his locker always has said, "THINK." Now his motto has become "WORK."

Fisk always has been a worker. In 1978 he caught 154 games (one off the record) and lost 34 pounds in the process. He's come back from three injuries that cost him half a season or more.

By season's end, he'll be 12th on the all-time list for games caught (more than 1,575), and Al Lopez' record of 1,905 is a remote possibility.

However, Fisk has never worked like he is now. The reasons are twofold. Back in 1983, Fisk and the late batting coach Charlie Lau finally finished a fullscale revamping of his swing that made him a very dangerous man.

"In Boston, I was a chopper, a real top-hand pull hitter. Now, I get the bat head out in front better and get more extension. That's because of Charlie Lau," says Fisk, who hit 26 homers, had 86 RBI and finished third in the MVP balloting in 1983.

Just when Fisk thought he'd build some peak late-career years, like Ted Williams, Hank Aaron and a handful of other hitters who prospered after age 35, his body let him down.

On opening day last season, Fisk suffered an abdominal muscle pull that was so deep in his stomach that doctors really couldn't identify or treat the pain. Rest was the only cure. Fisk went on the disabled list and missed 60 games. Still, he hit 21 homers and wondered what he could do with one healthy power season.

How much body work has he done since last fall when he hooked up with a muscle guru named Phil Claussen? "Hours, days, years," says Fisk. "I was much stronger before the season started but the schedule wears you down."

Yes, Fisk is so exhausted that he's hit four homers this week -- the one on Friday coming on his first at bat after being hit by a pitch. His slugging percentage is up to .541 (third in the league). And he's on a 107 RBI pace (with 54 so far). Tuesday will be his 10th All-Star game.

"Carlton's the MVP of this team, no question, and he's our leader, if we have one," said veteran Tom Paciorek before his recent release. "He's a Hall of Fame player and Hall of Fame guy, just like (Tom) Seaver. If he gets hurt, we're dead."

That Hall of Fame talk gets Fisk's attention because he knows he probably needs a couple more good years to be a lock. "Better mention it now," he laughs, "because in a couple of years nobody will care."

Like George Brett with Kansas City and Fred Lynn with Baltimore, Fisk is making a last-stand effort to drive his body to its limit one more time with modern training techniques. "If I owned a team," says Lynn, after wrestling with Fisk around the batting cage, "I'd make year-round weight training mandatory."

Of course, sweat and success aren't necessarily linked. Mike Schmidt went on a similar Mr. Olympia off-season program and his season's been a bomb.

Usually, the competitive flame burns out most quickly in catchers. Often, they feel used by their teams. "So what if you're bleeding like a pig inside," Fisk once said bitterly during a pennant race when he seemingly needed a court order to get a day off.

In those days, he called catching "the Dorian Gray position," because, while you look young on the outside, "you're turning to dust inside."

Now, somehow, that Dorian Gray syndrome has gotten reversed for Fisk. On a .500 team, he seems as motivated as a rookie. After just one bad practice swing in the cage, he will growl or howl or curse to make himself bear down.

After a draining ninth-inning loss to Baltimore here this week, Fisk said, "This game will make you cry. But it will make you laugh, too."

And he smiled.

The game was over and a demoralized fourth-place gang of White Sox was heading to the hotel. Fisk dressed slowly. He was in no hurry. A session of weight work almost as long as the game he had just played was awaiting him.

Last laughs are sweet. But very hard to earn.