Old ballplayers love spring.

If they can't do it in April and May, when their muscles are fresh, when the weather is cool and the open dates are forgiving, they know they'll never make it through July and August.

This has been the case since the days of the Delahantys and Deans, but the '80s seem to have brought us a new pattern. The quality veterans are lingering longer and staying respectable at older ages than of yore.

Dozens of old-timers--that's to say players past 35--catch our attention with deeds we thought we'd never see them perform again. In fact, entire teams built around veterans move into first place unexpectedly. Look how fabulously the old coots are doing, we murmur. Sometimes, we conveniently forget to look again in September and see how they finished.

The graying of the game is a definite trend, and perhaps a byproduct of the rich free-agent era, and this spring is just an elaboration of the trend.

The major league leaders in hitting and strikeouts are Rod Carew and Steve Carlton, both of whom will be 38 at season's end.

Tom Seaver and Don Sutton, also 38 and heading toward 300 victories, are among the game's ERA leaders; Seaver gives the miserable Mets respectability while Sutton (4-1) is holding the sore-armed Milwaukee Brewers together until Rollie Fingers (37 in August) can return--if, indeed, he can.

When did the game last have three effective pitchers who were 44, like Gaylord Perry, Jim Kaat and Phil Niekro?

The teams with (by far) the oldest starting lineups in their respective leagues, the Philadelphia (Wheeze Kid) Phillies and the California Angels, are both in first place.

The top of the Phillies' order looks like an alcove in Cooperstown, with right fielder Pete Rose (42), Joe Morgan (40 in September) and Tony Perez, who was hitting .316 as of his 41st birthday Saturday. When the Phils open the bullpen door, out step Ron Reed (40) and Tug McGraw (39 soon). No wonder Carlton feels young. On this team, he is.

The Angels have learned not to fear birthdays, either. Tommy John will be 40 next week, which should make the rest of the ancient Angel rotation, Geoff Zahn (36) and Ken Forsch (36), feel a little less decrepit.

The California lineup is older than rock. Bob Boone (35), Carew and Reggie Jackson (37 on Wednesday) are just part of a squad with 17 players who are past their 31st birthdays. Stats say that in baseball age starts showing at 32. By the time you're 36, the Baseball Encyclopedia says you're supposed to be dead.

Don't try to convince the first-place Baltimore Orioles of this, not when Jim Palmer (37) is still their name pitcher, while three of their best bats belong to Al Bumbry, Ken Singleton and John Lowenstein, all of whom are 36 this season.

The prime symbol of all these vernal veterans is Carew, hitting .442.

When Carew's batting average reached .500 on May 6 (48 for 96), it was a new major league benchmark of sorts: hottest start by a player who claims he'll retire after the season because nobody appreciates him.

Few would dispute that baseball now has more conspicuous over-40 players, and more over-35 stars, than ever in memory. But nobody's quite sure why.

The cynic's explanation would be that the quality of the sport has declined in the last 25 years as the game's available talent has been diluted among 26 teams, rather than 16. Naturally, the old codgers hang around longer because the talent pool has been watered down.

The feeling here is that baseball has increased its base of quality athletes in every decade since the '50s. Whatever may have been lost in finesse (and even that is debatable) has been more than made up in physical talent, particularly in the huge influx of players who possess both base-stealing speed and extra-base-hitting power. Let's try a simpler explanation for Gray Power.

Better conditioning and greed.

In the last decade, baseball has finally accepted the sort of sophisticated year-round training, conditioning and strengthening programs that almost every other sport adopted years ago. Baseball is just catching up with football, track and the Olympic sports in common sense. Any vet will tell you that 15 years ago players reported to spring training to get in shape; now, they arrive earlier and are already near peak condition on the first day.

Carlton would rather stick his left arm out of a moving subway than miss a day of his exhausting Kung Fu rituals. Lowenstein, who discovered he was a slugger after he turned 35, cries himself to sleep at night wondering what he could have been if he'd discovered the strength-with-flexibility style of weightlifting 20 years ago. They have plenty of company.

The motivation for such arduous conditioning is obvious: money. The big bucks only began arriving in the late '70s. When you can make as much money in your 20th year as a professional as you did in your first 15 seasons combined--and that's a commonplace state of affairs today--you're going to beat that health-spa equipment to death in December.

Baseball has always had a few individuals who understood that, if you were dogged and savvy enough, you could be great past 35, and even 40. Warren Spahn won 20 games seven times after his 35th birthday. Hank Aaron averaged 41 homers a year between 35 and 40. Ted Williams hit .337 over six seasons from age 36 through 42; he batted .388 at 39 and won a batting title at 40.

In their day, they were thought to be physical freaks. Normal men couldn't do such things, not on willpower and work alone. Why, you can't beat time.

Now, Spahnnie, the Hammer and Teddy Ballgame just look like they were ahead of their time.