When Jack Nicklaus, Tom Watson, Gary Player and Tom Weiskopf got to the 18th green of the Augusta National today, all the side bets in their practice-round match on the eve of the Masters were on the line.

Watson's ball was in the fringe, about the same distance from the hole as he was on the 71st hole of last year's U.S. Open.

"I told Tom, 'If you chip this (one) in, I'm going to bury this putter right in your head,' " recalled Nicklaus.

What happened?

"He chipped in for all the cash," said Nicklaus with a laugh and a shrug.

Thus ended a round of needling in which, according to Watson, he called Nicklaus "old and bald" and Nicklaus kept telling him he was too cocky.

Long knives are being sharpened here this evening in preparation for the 47th Masters, the event Nicklaus says "marks the beginning of the golf year."

To the kings and princes of this sport, the 13 tour events so far this season have just been for practice and profit. Now, the real golf starts.

As usual, the same glamor names dominate all speculation here. If thunderstorms (predicted for the next three days) allow it, this Masters should be another private, semifriendly grudge match among a dozen or so famous names.

This is the day for thumbnail sketches of familiar figures, for cryptic quotes from the great into which golf fans can read portents.

For instance, the three most conspicuous gentlemen here--Nicklaus, Watson and defending champion Craig Stadler--have all had winless springs in which their play has ranged from spotty to downright ugly.

All three, however, claim to have made discoveries in recent days.

Nicklaus was lining up all his shots too far to the right until the wife of architect Pete Dye gave him a lecture at the TPC and got the Bear straightened out. Now, Nicklaus says, "I'm hitting the ball much better.

"I'm very hopeful of how I might play . . . if my short game and putting can handle the (fast) greens."

Watson, only 30th on the money list, has putted so mortally all spring that whispers have been heard that, at 33, he's finally discovering that you're not supposed to make all of those 25-foot putts.

Arnold Palmer started getting the message at about that age and won only one major after turning 33.

Watson, however, says his touch is returning, especially inside 10 feet "and on this course, putting is more than half the game."

"My long game isn't as strong as I'd like it to be," added Watson. "But, you know, the golf swing is like a light switch. You're fumbling around and you find the switch and all of a sudden everything is clear."

Has he found the switch ?

"It's very dark," said Watson with a rueful smile.

Of this trio, Stadler has the most tangible reasons for confidence. The '82 money leader noticed last week in Greensboro that his right index finger was wrapped around the putter instead of extending down the shaft--an eccentric Stadler trademark.

Immediately, he began draining everything and finished second. "My confidence (putting) is up to about 90 percent, compared to 5 percent before," snorted the Walrus. "And those 5 percent were when I closed my eyes.

"I like my chances . . . I consider myself one of the best putters on very fast greens . . . I see no reason why I can't repeat," continued Stadler, knowing that Nicklaus ('65-66) is the only player ever to repeat. "This course makes me swing well for some reason."

While Watson, Stadler and Nicklaus may be the chalk, plenty of other names are mentioned frequently here.

Lanny Wadkins, a notorious streak player, won at Greensboro by five shots. Despite only one top-10 finish in 10 Masters tries, he's a credible dark horse.

Tom Kite has five finishes in the top five in the last seven years here. He's especially pleased that the 13th and 15th holes have been lengthened a bit this year.

Since Kite always has to lay up and make birdie with a wedge and one putt, he'd like everybody else to face the same task.

Ray Floyd has this track wired. Seve Ballesteros, like Watson, is a long, sometimes wild driver with a great touch who loves Augusta's enormous, forgiving fairways.

Tom Weiskopf, hitting it a ton off the tee, and Johnny Miller, a winner at Inverrary, have been runners-up here four times and three times, respectively. The course loves 'em, but they have bad pressure memories.

Youngsters Hal Sutton and Bobby Clampett have been hot on tour, but neither has played well here.

Among the gorilla longshots are Fuzzy Zoeller, Greg Norman and Dan Pohl, who lost to Stadler in a playoff last year the first time he played here.

Ben Crenshaw, David Graham, Larry Nelson and Hale Irwin (who won the par-3 contest today) expect to see their names on the leader boards, while players of roughly equal accomplishments--like Lee Trevino, Bill Rogers, Calvin Peete, John Mahaffey and Isao Aoki--arrive here with no hope.

There have been a few minor changes this year. Nicklaus, the architect, helped redesign and tighten the fourth hole.

Also, in response to protests from the pros about the unreliability of Masters caddies, the players are now allowed to use their normal tour caddies. Most will.

Spring rains have made the greens much softer than usual, so high-ball hitters may not have quite their normal advantage.

Nonetheless, all the old truths apply here. Hit it long. Read every putt to break toward the 12th green ("It took me eight years to learn that," said Nicklaus). And make a world of eight-foot comebackers on the diabolically fast bent-grass greens.

Many a guess has been made this week on who will capture the 47th green jacket. Only Nicklaus had a different answer when asked to be a handicapper and name his half-dozen picks for the week.

"When I stop playing," he said, "then I'll name somebody else."