Professional golfers make money the old-fashioned way.

They earn it.

In most other American money games, an athlete can live off his past like a camel living off his hump. In baseball, a player who has one decent year can -- with luck, a shrewd agent and a pliant owner -- parlay a smidgen of compoetency into a multiyear, million-dollar contract. Any NBA player who isn't rich and secure far beyond his deserts is the exception. Even the NFL, that bastion of unblushing owner monopoly, has its fat long-term contracts.

On the PGA tour, you cash a check as long, and not one day longer, as you retain the ability to sweat blood over a six-foot putt and drain that rascal down the hole's unfeeling heart.

There's no scene in pro sports like the cut. A golf locker room at sundown on Friday is a bleak place as half the players in a tournament await word that their pay for the week will be $0.00. To them, the cut is the essence of their game; it epitomizes the sharp edge of true competiveness that gives their sport distinction and themselves a special dignity. For the vast majority of pro golfers, the cut is what the game is all about.

"Because we dress well on the course people think we're all millionaires," said 36-year-old Ed Sneed, who in a dozen PGA seasons has won an average of $50,000 a year. "The truth is that there is less money in pro golf than in any well-known sport. Out of the 144 guys here, at least 100 are extremely concerned about their next check."

As Sneed says this, his face is drawn from tension and annoyance. Currently, he is where he has spent most of his pro life -- 50th on the year's cash list and perpetually concerned about the state of his game and the vicissitudes of the leader-board.

His two-day total in the Tournament Players Championship is 77-76 -- 153. Half the field is still on the course. "I think I'll miss the cut by a stroke," he says, "but if the wind whips up, I could get lucky. Anybody who thinks I'm indifferent to this is crazy. I came here to play. Hell, good rounds on Saturday and Sunday and I could go from last place to the top 10."

At evening, the wind dies. The cut demarcation dips to 151. Sneed's gone. His expenses for the week are nearly $1,000. A week of his life has been a waste. He'd have saved money if he'd stayed home and fished.

"In golf," Sneed says, "there is no team bus, no team meal, no team hotel. When I see a player in another sport who's making $800,000 a year guaranteed, and you know that he's not really giving 100 percent, it galls me."

Players are magnetically drawn to the scoreboard on Fridays, trying to walk past it nonchalantly as they count the players with better scores than theirs. The cut is always "top 70 and ties." Sometimes, however, a pro will simply sit and stare for an hour at those numbers as they grind him down then boot him out of the tournament.

"Last year, Tommy Aaron ('73 Masters champ) came into the press tent at Westchester and sat down next to me," recalls tour official Steve Rankin. "I barely knew him, but he started talking . . . had to have somebody to spill his guts to. "I just can't get over the hump,' he said. 'Whatever it takes to miss the cut, that's what I shoot. If my putter would just start coming around . . .'

"I kept thinking, said Rankin, "that for every Watson and Trevino, there are dozens of guys out here who have to battle their brains out every week."

Even the tour's money list, which pales beside the salaries of other sports with only 44 $100,000 winners in '80, is deceivingly high.

"It costs me $50,000 to $60,000 a year just to live on the tour," says Jim Simons, who had a typical $85,527 season in '80 (48th place). "I suppose I could live a little cheaper if we cut to the bone, but this is my family's life. We're on tour a lot more than we're home. How can I ask my wife and two children to live in motel rooms most of the year? I don't live fancy or eat fancy, but if I have to pay $800 a week for a condo where we're playing, I'll do it. If it's a choice between flying or driving 500 miles, we'll fly. I'm not going to make us all unhappy and mad at each other just so I feel a little more secure.

"After all, if the babies are crying and daddy can't sleep, then daddy's not going to make any money that week."

Perhaps the oddest aspect of tour life is the way it fosters independence and dependence simultaneously.

"Because you have to dig every dollar out of the ground yourself, you don't feel beholden to anybody," says John Mahaffey. "Because you're a one-man corporation, you're very independent. You're your own manager and general manager and owner.

"But it can make you feel very alone. In '77, I fell to $9,000. I had house payments and wife payments. You know, an ex-wife doesn't want to hear that you've developed a slice. She wants to see that check in the mail. I'd won over $100,000 in three different seasons, but I had reached the point where I could see the bottom of the bank account. Another bad year and I was broke.

"There's something about golf that is like the American dream," said Mahaffey. "It's strictly merit. What you did even one week before does you no good at all. But there's also something very, very tough about this life."

In no other sport are standards more sternly fair. Golf has no quibbling about statistics or intangible values. Your score is an absolute; it's not how, it's how many. Your style, your strategy is your business.

For instance, on Thursday, Johnny Miller was in seventh place in the TPC. However, he also wanted to see his college, Brigham Young, play in the NCAA tournament that night. So he flew to Atlanta, watched his team win, then flew back to Sawgrass at 3 a.m. That morning, his tee time was before 8 a.m.; Miller started with three bogeys and shot 74. Maybe his decision was dumb. Maybe it will even cost him a championship. But nobody could fine him, fire him or even criticize him. As always in golf, it was his affair.

Oddly, such complete self-reliance doesn't always carry over into other facets of life. "Players tend to become too dependent on golf," says Labron Harris, former player and PGA official. "Too many are reluctant to branch out and discover their other skills."

One who has recognized that pitfall is Simons. "I get very tired of playing competitive golf. Every part of the game is a continual battle," he says. "My wife says, "The longer you play, the more you work.' I admire the way Nicklaus drives himself, strictly for pride. But I have to do it mostly for money."

But not entirely. "I'll miss the adrenaline flow in competition," says Simons. "I've searched for something else that will juice me like that." For him, it proved to be becoming a licensed stockbroker last winter. Yes, he's going to make money the old-fashioned way.

In an era when many, perhaps even most sports, have a problem convincing fans that their athletes are not pampered and complacent, golf retains a sort of cruel purity -- a knife-edge called the cut.

On Friday evening here, Ray Floyd came into the press tent after dark to stare at the huge scoreboard. Just a week ago at Doral, Floyd won $45,000. He is one of the few with the wealth and prestige to relax if he wishes. Floyd look thoughtfully at the board, digesting the numbers and the names that went with them.

What are you doing, Ray?

"Just looking for my friends," he said.