Sometimes it seems that baseball reincarnates the same performers -- one of a type per generation.

Right now, two pitchers who epitomize completely opposite archetypes are having landmark seasons.

Dwight Gooden is continuing the exalted tradition of pitchers with overpowering stuff. It runs like a straight line from Walter Johnson to Lefty Grove to Bob Feller to Sandy Koufax and, now, to a 20-year-old with the New York Mets who hasn't allowed a run in 31 innings.

More dazzling than Gooden's 21-4 record, more bewildering than his raw skill, more inexplicable than his control is his almost complete mastery of his craft at an age when he can't buy a drink in some states.

Since 1919 and the last gasp of the dead ball, only two pitchers ever had title-eligible earned run averages lower than his current 1.62. And both of those -- Bob Gibson (1.12) and Luis Tiant (1.60) -- came in the freak season of 1968, when the conditions of the sport were so unfairly skewed in favor of pitchers that the game's strike zone had to be changed.

While Gooden rises in the firmament, approaching historic stature with stunning swiftness, another man, who never won a big-league game until he was 26 and never won 20 until he was 30, is completing one of the sport's least heralded major monuments.

Across town at Yankee Stadium, Phil Niekro is on the brink of becoming the first knuckleball pitcher to win 300 games. At age 46, with a trick pitch that barely breaks the speed limit for automobiles and a fast ball on which "they refuse to put the radar gun," Niekro offers the sort of mind-bending contrast to Gooden that only baseball offers.

If Gooden and Niekro were to meet in the World Series, which is possible, it would seem almost inconceivable they were part of the same athletic species. One seems to need a rocking chair, not a pitching rubber, as he tries to slow his dancer down toward 50 mph, whereas the other gent, hurtling close to the 100-mph barrier, looks like a laboratory creation.

While Gooden continues and may in time expand the dimensions of a pitching tradition, Niekro fears that he could be among the last of his bizarre breed.

"I don't want to see the knuckleball die," Niekro said last week. "Except for my brother Joe, who's 40, and Charlie Hough (37), there are no knuckleballers, not even in the minor leagues . . . Not a one that I know of . . . If I have to open up a knuckleball school to keep it in the game, I will."

Niekro's place in the game is secure. If Hoyt Wilhelm was the best knuckleball reliever, then Niekro is its best starter, easily surpassing Wilbur Wood, who won 20 games four times, and brother Joe, the only other 200-win flutterballer (202).

Niekro has been so durable and such a tough game-situation competitor because, unlike other trick-pitch customers, he is not totally dependent on his butterfly. If he must throw a strike, he has a sneaky sinker and slider that he uses to shave corners.

"I'm just below hitting speed. If I threw any harder I'd be right in the BP (batting practice) range," says a laughing Niekro, who is scheduled to make a third try for No. 300 Tuesday in New York.

"By the time you say to yourself 'It's spinning!' it's on top of you and you've hit a pop-up or a grounder," says Toronto catcher Ernie Whitt.

A more tangled problem, perhaps for the rest of this century, will be to figure out where Gooden's name belongs on our all-time list.

Before going overboard, we should note that Smoky Joe Wood went 34-5 with a 1.91 ERA and 258 strikeouts at age 22. He won only 35 more games the rest of his life and became an outfielder. Every baseball fan also knows about Herb Score's eye injury and Mark Fidrych's dead arm.

Now, let's go overboard.

Talk to big-league players or veteran managers and the consensus already exists that you can't pitch much better than Gooden is right now.

To find proper historic comparisons you must limit the field to pitchers who could consistently win 25 games, strike out more than 250, walk less than 80, allow only two runs a game and win 75 percent of their decisions.

How many names, other than Johnson, Alexander, Mathewson, Grove, Feller and Koufax in their primes, come to mind?

Gooden's career ERA is 2.05 and his record 38-13. Since Aug. 6, 1984, when he last pitched what could be called a bad game, Gooden's mark is 29-5 with an ERA of 1.49. From that date to this, he's had one start that could be called embarrassing (by his standards) -- a five-run, five-inning outing a month ago. In his six beyond-belief starts since then, his ERA is 0.75 with 55 strikeouts, 10 walks and 30 hits allowed in 48 innings.

"When I look at Dwight, I just try to imagine what he'll be like in seven years, when he gets stronger," says teammate Keith Hernandez. "I just pray to God I'm on the same team with him."

What Gooden might become, considering his diligence, gentle temperament and love of learning, gives fans chills. He's already forsaken strikeouts as a goal in favor of efficiency, dispatching a demon distraction Nolan Ryan and Sam McDowell never escaped. They struck out their own greatness.

To his credit, Manager Dave Johnson has treated Gooden as if he were the most precious property in the game's history. Which he might prove to be. No one's ever been so good so young.

Twice this month, Gooden has gone nine scoreless innings against, perhaps, his two main rivals in the National League -- Fernando Valenzuela of the Dodgers and John Tudor, who is on an 18-1 streak with St. Louis. Both times, the score was 0-0 after nine. Both times Johnson took Gooden out. The Mets won one, lost the other.

"He's going to be here long after I'm gone," said Johnson. "I'm not going to let him go beyond 130-140 pitches, even if it's the last day of the season (against the Cardinals) for the pennant.

"Well," amended Johnson, "maybe if it's the last day."

"This Saturday (against Pittsburgh) could be a big day for me," said Gooden after his Monday shutout.

Because you could break Jerry Koosman's Mets record of 31 2/3 scoreless innings?

"No," said Gooden. "Tom Seaver holds the team record for hits by a pitcher in one season with 18. And I've got 17 now."

Vain only about his .205 batting average, Gooden can't wait to learn more about pickoff moves, fielding, bunting, changeups and hitting. Team victory, with the grubby, drudgerous details that lead to it, is Gooden's only north star. Yes, he's scary.

If Niekro does open a knuckleball school, the commissioner should pass an edict in the best interests of the game. Gooden should not be allowed to enroll.