Behold the expansion Mariners, who do not pitch tents in courtrooms, drink motor oil and eat light bulbs, or cry public tears over the rigors of making a zillion dollars. None of them makes a zillion dollars, but they probably wouldn't complain if they did.

Nels Peterson, the Minnesota Twins' 72-year-old clubhouse guard, calls the Seattle baseball players - The most pleasant group of gentlemen this side of The Space Needle." In an age when so many front-runners snarl and bicker. why is this lowly first-year team a model of manners and brotherly love daring the dog days of August?

Because expansion has made them major leaguers.

"Probably at least half of these players would be in Triple-A ball right now, or bouncing up and down to the minors," says manager Darrell Johnson. "No matter what takes place here, it has to be better than the minor leagues."

The only commotion in the Mariners' locker room was on the first day of spring training. when players walked around, spinning each other like tops to read the unfamiliar names across the backs of the uniforms.

Now that everyone has been properly introduced and has shared hardluck stories, the clubhouse is quiet, unless Lee Stanton is in one of his rope-skipping moods. or part owner Danny Kaye is telling a joke.

There is no griping, no pressure, no millionaire on the roster. Pitcher Dick Pole does not kick Coke machines as he used to. There is also no chance for a pennant this year, but no one expected one. This is an expansion team, which in pro sports has always meant a ragtag bunch.

But the Mariners have pleasantly surprised baseball. They have drawn more than a million fans to the King Dome and have played .500 ball since mid-May. And, even more astonishingly, they have taken delight in the alleged tedious trappings of the game: signing autographs, flying to Cleveland, speaking at luncheons.

There is an unspoken doctrine of baseball that states that the most difficult part of the game is not, as some believe, hitting the curve ball - it's playing with enthusiasm day after day in hot, humid August, when the club hasn't a prayer of a playoff berth.

The Mariners have overcome this hardest assignment in baseball. They are cheerful, enthusiastic, considerate - big league off the field.

Veteran baseball writer Hy Zimmer-man of the Seattle Times is downright (See MARINERS, D3, Col. 1) (MARINERS, From D1) fond of the team. Coach Don Bryant carries Zimmerman's typewriter if an airport walk is lengthy. Pole gave his seat to Zimmerman on a 45-minute bus ride through simmering Texas, even though it is a commandment of pro travel that in a crowded bus, ballplayers sit and others stand, and Pole was pitching the next game.

J. Michael Kenyon of the Seattle Post-Intelligencer also enjoys covering the Mariners. "One thing I like about this group." said Kenyon. "They don't try to disguise their bashfulness with a cocky camouflage.Thet're the same in the dugout as they are in a hotel lobby."

Johnson treasures the atmosphere and says. "no one will destroy this."

The team is saved from dullness by their child-like exuberance and players like Glenn Abbott, Steve Braun and Ruppert Jones.

Like so many of his teammates, Abbott has experienced a baseball rebirth in Seattle. After never winning more than five games with his previous major league team (Oakland), Abbott went into tonight's game 9-7, with a six-game winning streak.

"(A's owner) Charley Finley had no confidence in me. I was like a yo-yo over there," said Abbott. "It seemed like every time I lost a game, I was sent down. I was beginning not to like baseball.

"It's completely different here. We don't have that pressure of being sent down, of winning a pennant. I have more confidence. I sleep better. And I get along with my wife better. I hope I can stay here. I like everything about it."

Abbott, who chews tobacco on the airplane and spits neatly into a cup, is one of 11 Mariners who already have purchased homes in the Seattle area. He has made his best effort to plunge into the local life-style.

A Seattle restaurant owner took Abbott and teammates Larry Cox, Tommy Smith and John Montague fishing on his boat in the Pacific.

"I was all fired up," Abbott recalled, "and then all of a sudden, here comes my cookies, and then all of a sudden. everyone's catching fish while I'm barfin'."

Abbott says he had a great time and will go again soon, even though he rues his standing in the seasickness league: "In three trips ocean fishing. so far, "I'm three for three."

Braun also is a character. A 288 career hitter, he is currently in an ugly slump (226) but refuses to kick a water cooler. Instead. before Wednesday night's game against the Orioles, he emerged in the dugout with an Ace bandage wrapped around his neck and head, forming a cone topped by his blue Mariners cap.

Someone politely inquired, "Are you from Star Wars?" (Remember, not long ago these guys were stangers).

"No." Braun said. "Everyone in the locker room was taping up ankles and wrists and things, and the only thing that's bothering me is my head. So I taped my head. I'm going to play like this. I'll do anything to get out of this slump. This is the first time I've had my head together in six months."

The team's all-star is Ruppert Jones, who is being touted as a rookie of the year candidate to challenge Baltimore's Eddie Murray. Jones has 20 home runs and serious visions of himself cast in bronze in the Seattle outfield one day. He says, straight-faced, "I want to be great," and his teammates, at least, are listening.

Especially best friend Carlos Lopez, the son of a well-to-do family in Mazatlan, Mexico, who runs through signs at third base. Tagged "the Merry Mariner from Mazatlan," Lopez knows little English and decided to pick up the language from his buddy Ruppert.

Consequently, Lopez' favorite word is a rather common locker-room obscenity.

Alas, the confused Lopez must pick his spots to practice his newfound linguistic Prowess. The gentleman Mariners voted to fine any member of the team $1 for blemishing the conversation in their clubhouse with that particular word.