Usually, Jim Palmer and Steve Stone are the most urbane of ballplayers. Nothing disturbs their spotlessly handsome exteriors or rattles their analytical approach to baseball. Above all, neither doubts himself.

That is, until now.

One, or both, may be pitched out.

This spring, the former Cy Young winners are fighting for their baseball lives. Against each other. Already, the strain shows.

Palmer, 36, and Stone, who'll be 35 this season, had losing records last year. Stone collapsed from 25-7 to 4-7 with a 4.57 ERA; Palmer fell to 7-8. Both now covet the same job: the final spot in the Orioles' starting rotation behind Scott McGregor, Dennis Martinez and Mike Flanagan.

Their earnestness hardly can be overstated. Palmer and Stone believe--with their whole careers as evidence--that as starters, they can still be stars, but as part-time "swing men" they're bound to fail.

One is going to get the ball every fourth day. For him, it will be a square-business chance to prove his days of greatness aren't over. The other is going to get the ball only, as Stone puts it, "with a string attached." That is, infrequently and at capricious intervals. For that fellow, 1982 could be the beginning of the end.

"This spring training is a separate seven-week season for me," says Stone, who has been so anxious to avoid this showdown that, over the winter, he asked the Orioles three times to trade him.

Instead, the Orioles merely reconfirmed what they already knew: because of their age, history of arm problems and recent failures, Palmer and Stone have almost no trade value. "I'm aware that no one is going to give up their first-born in trade for me," says Stone sardonically. As for Palmer, nobody even nibbles any more.

"I don't want to go out as a fifth-starter swing man," pleads Stone. "Thirteen years of (big league) experience tells me that I have almost no value in that role. I'm 87-58 (career) as a starter and 20-35 as a swing man . . . I've said to the Orioles, 'Let me show you I can win like I did in '80. Give me a set time before opening day and decide by then whether or not I'm in the rotation. If I'm not, then let me go or release me.' "

What worries Stone is that he's not in a position to make ultimatums. Signed through 1982, he has little leverage. The Orioles view him as a one-year insurance policy. If somebody gets hurt, or flops, give old Steve a chance.

As a free agent after this season, he has the perfect built-in motivation; a good year could be worth a million bucks in a new contract. Stone can plead, as he does, "Trade me, start me or release me," but he has to say it with a pretty-please tone of voice. Basically, the Orioles can do with him as they please.

Ironically, just one spring ago, Stone and Palmer--known as "Pebbles" and "Cakes" to teammates--seemed on the verge of distinguished baseball old age.

Then, Stone was unwrapping a 1980 Cy Young trophy; it was Steve Carlton's, not his. That was a portent. Also last spring, Palmer came off a 16-10 season in which he seemed to have learned to survive the loss of his Hall of Fame fast ball. Palmer even had become a disciple of Stone's positive-thinking and pregame meditation methods.

Now, Stone is reduced to the old-pitcher litany of explanations of how an off-season elbow rehabilitation program has restored him.

Palmer is in a funk, acting fitfully depressed here. His arm feels "lousy." After just four days in camp, he has other Orioles rolling their eyes by saying, "I think I need a (cortisone) shot (in the shoulder)." As for all that Stone-clone positive thinking, Palmer mutters, "Takes too much energy." When prodded with some inane gonna-have-a-great-season-Jim? remark, Palmer responds, sarcastically, "Probably not."

"You can't blame Jimmy for getting in bad moods," says catcher Rick Dempsey. "He's used to always being viewed as a plus."

The Orioles try to put a cheerful face on the Palmer-Stone competition.

"It's the ideal situation," says Ray Miller, the pitching coach. "You're talking about two men who are 'pitchers' in the broadest expanse of the word . . . Having Stone push Palmer or Palmer push Stone is better than having me push them both."

Robert Frost's bitter line, a sort of recurrent baseball epitaph that seems applicable every spring, fits this pair: "No memory of having starred atones for lated disregard or keeps the end from being hard."

Stone is particularly antsy. He knows what history says will happen in April and May. Palmer will be starting and Stone sitting.

From Mike Cuellar to Brooks Robinson to Boog Powell to Paul Blair to Mark Belanger to Lee May to Palmer, Manager Earl Weaver has shown an unvarying pattern of sticking with his old stars longer than any other current manager. The last man to lose faith in Palmer will be Weaver. And, should Palmer fail so unequivocally that he must finally be hooked, the last man to lose faith in Stone also will be Weaver.

Which brings up an interesting twist. If, out of the quartet of Paul Moskau, Ross Grimsley, Don Stanhouse and Dave Ford, two or three work out well enough that Sammy Stewart is no longer needed in the bullpen, will the defending ERA leader get a chance to start regularly this season?

To all this, Weaver says with proper noncommital neutrality, "This is what we come to Florida for . . . to look at all our options."

Nonetheless, the single most vital cog in the Oriole machine of 1982 may be the contribution of the aging, classy creature known as James Steven Palmer Stone.

If each redeems himself, Oriole hopes will have no limits. If even one is a solid 16-game winner, the pitching staff could easily look like the 100-win grinding machine of 1979 and '80.

However, if the Pebbles and Cakes of this season repeat their failures of last year, the Baltimore Orioles might as well stay in Florida, because, by the time loyal Earl Weaver runs out of patience with his two aging Cys, the pennant will have long since flown away.