If we continue to follow our basic assumption that pitching is the key to baseball crystal-gazing to its logical consequences, then we are left with rather bloody and drastic conclusions regarding the National League.

A prognosticator with pitching myopia is forced to conclude that Philadelphia probably cannot repeat as division champ, let alone as lord of all baseball. The Phils's starting rotation, as cracked as the Liberty Bell all of last season, has been further weakened by the loss of Whirlybird Walk and Randy Lerch. The Phils, like the '79 world champion Pirates, needed to spend their offseason doing anything necessary to add a good starter; instead, they've gone backward.

The Montreal Expos, eliminated on the last weekend in each of the past two seasons, have such a clear mound superiority in the East that, unless their aged bullpen collapses, they should finally give the baseball world what it needs least -- frigid playoff games in Canada in October.

The popular Pirates, their staff built on the flimsy foundation of perennially injured John Candelaria, Don Robinson and Rick Rhoden, are probably on a downward slide.

The completely shuffled St. Louis Cardinals have an all-new team and an all-old pitching staff that could produce a flag only if the whole division regresses to a sub-90-win level. The Cards retain their lock on the triple-crown booby prize of pitching -- last in ERA, last in saves, last in strikeouts. When Whitey Herzog arrived, he said, "We need three kinds of pitching. Left-handed, right-handed and relief." With the addition of Bruce Sutter, he's one for three; are from sufficient.

In the NL West, Houston has the best pitching on paper and Los Angeles has the best pitching on prospects. The Astros, with their rotation of million-dollar men, ought to repeat, perhaps with ease. No team can match Houston's combination of starters (Joe Niekro, Nolan Ryan, Don Sutton, Bob Knepper, Vern Ruhle and, perhaps by midseason, J. R. Richard) and relievers (Joe sambito, Dave Smith and Frank LaCorte). The Dodgers must resort to dreaming of a storybook season from something called Fernando Valenzuela, which is a either a chubby 20-year-old left-hander who will be the '81 rookie of the year or a remote mailing address in the lower Andes.

The rest of the West is led by Atlanta and Cincinnati, two teams with formidable hitting that don't know where their next 15-game winner is coming from. If either of these teams gets to the World Series, then next spring in this space we will have a story that begins, "Since 80 percent of baseball is hitting , why don't we . . ."

Perhaps the team in baseball with the most conspicuous need is the champion Phillies. This club, far from being a juggernaut since it ranked a modest sixth in wins last season, prospered in postseason in large part because that is the one time of year when least emphasis is placed on fourth and fifth starters.

If you've got Steve Carlton (24-9), Dick Ruthven (17-10) and genuine prospect Marty Bystrom (5-1), then you can fake the rest in October, especially if you have a reliever like Tug McGraw who is on the streak of a lifetime (0.52 ERA after the All-Star break).

In the last month, the Phils have tried desperately to set up a three-cornered deal that would get rid of grumpy Greg Luzinski and young Walk (whose value is at its highest now), while bringing them outfielder Gary Matthews and one of the Chicago White Sox capable young left-handed starters.

Nice idea. Awful execution.

The Phils succeeded in getting Matthews for Walk, creating a three-way logjam in left field that made Luzinski's departure imperative. Then, to their shock, the Phils found out Luzinski's open-market value in terms of front-line pitching: nil. Finally, they had to settle for Chicago cash. And cash can't pitch.

This is what you call a potential disaster. The Phils had already given up on Lerch (4-14) and are close to reaching the point of disgust with great-looking Larry Christenson (19-5 in '77), who, two years in a row, has mastered the five-win season. What if Carlton only wins 20? What if McGraw, whose ERA was 5.19 in '79, returns to mortal status? What if Sparky Lyle, who was fat before he gained another 20 pounds, is only so-so? What if oftinjured Dick Ruthven . . .?

All this does not mean that the Expos are a shooin, not since the '80 Phils learned the virtues of true grit. Montreal has never proved that it is a clutch team.

The Expos will have to prove that the corrosive clubhouse influence of Ron LeFlore (a one-year, here-and-gone nightmare), me-against-the-world Rodney Scott and Ellis Valentine has not soured this club's competitive edge. The key to the Expos may be the vastly talented Valentine (67 RBI in 311 atbats), who was hors de combat the second half of the year with injuries.

Pitching cures many ills and the the Expos have the arms. Behind Steve Rogers and 24-year-old Scott Sanderson, both 16-11 and capable of even more, come Bill Gullickson, 22, who was 10-5 in a half-year with an 18-strikeout game, and solid young David Palmer and Charlie Lea. Woody Fryman, 41, is the class of a makeshift bullpen, and in the past two years he had been asked to warm up (by actual count) 525 times. On the day old Fryman can't raise his arm, the Expos chances droop dramatically.

Perhaps the most predictable known factor in the NL ought to be Houston, a team with too much pitching, speed and Bill Virdon-taught discipline not to play at least 15 games over .500, but not nearly enough power (75 homers), competent catching or quality infielders to threaten the 100-win status of great teams.

Houston's biggest problem may be management power struggles. Everybody and his brother will be trying to grab the know-nothing ear of owner John McMullen, the baseball novice who fired '79 NL executive of the year Tal Smith.

The Dodgers are the perfect example of a team with absolutely consistent year-to-year hitting that has its place in the standing determined by the changing state of its pitching staff. In the last four years, L.A. has hit 109 more homers than any other team in the NL. Although the Garvey-Cey-Smith gang has been uniform, L.A. pitchers have been a trip: Doug Rau, 15-9 to 1-5; and Rick Sutcliffe, 17-10 to 3-9, being typical of almost a dozen migraine-inducing Dodger hurlers. In the last four seasons, the Dodgers have led the league in ERA twice and been to the Series twice. Once, they finished second in ERA and were second in the division. And once, in '79, they dropped to seventh in ERA and were eighth in the league in wins and finished below .500. Any questions?

After losing both Tommy John and Sutton, L.A. ought to be sliding, but the team with the NL's best history of producing young arms has three more classy products arriving -- Steve Howe, Joe Beckwith and Valenzuela.

Two contending franchises whose histories may intersect each other this year are the traditionally built Reds, strong in fundamentals, and the store-bought Atlanta Braves, constructed on grotesquely over-priced free agents.

The best inside evaluation of the Reds comes from Johnny Bench, who has adamantly refused to play more than two games a week behind the plate. If Bench thought the Reds has an honest shot at another Series visit, do you really think the best, and perhaps guttiest catcher in history wouldn't squat for one more year? Bench senses the true state of affairs and he's putting Johnny first.With Bench at any other position, the Reds have no chance since his catching replacements are all weak hitters and the mediocre Cincy staff needs all of Bench's pitch-calling savvy.

The Braves have fine young sluggers in Bob Horner and Dale Murphy, but the gentleman who holds the purse strings, and meddles in the baseball judgments -- Ted Turner -- has the heathen lack of sensibility that one might expect in baseball's most irresponsible owner. He can spot a hitter (anybody can), but on pitchers, Turner might as well consult a psychic. The Braves aces are Phil Niekro and infernal cheat Gaylord Perry, both of whom are 42 and coming off losing seasons.

The good-news team of the National League may be the San Diego Padres. After years of losing with big free-agent names, they may now play respectably with an anonymous cast collected by GM Jack McKeon and managed by Frank Howard.

Perhaps the clearest proof of the relative importance of hitting and pitching in baseball crystal-gazing is the case of Dave Kingman, the player who, in recent years, has had the best ratio of home runs to at-bats of any player in the game. Some people maintain that the Chicago Cubs just traded Kingman to the New York Mets. Others are sure 'twas the opposite way around. It's easy to forget which. And, since both teams together couldn't mount one good pitching staff, it doesn't matter either.