This is an anniversary for Ken Singleton.

Today completes one full month of the worst batting slump of his career -- a nightmare of self-doubt, mounting pressure, paralysis from analysis, plus bad luck and a few flu germs -- that has helped drag Baltimore down to fourth place.

For one month, Singleton, the major leaguer with the highest career on-base percentage (.401), has both batted and slugged .151. In his last 93 at-bats, he has 14 singles and no extra-base hits.

Nothing is more mysterious than a slump, especially when it happens to a switch-hitter who, for the last dozen seasons, has been the hardest man in baseball to send back to the bench without either a hit or a walk.

To put Singleton's miseries in even starker and crueler relief, the batter behind Singleton, switch-hitter Eddie Murray, has been as hot as Singleton has been cold. In his 41 second-season games, Murray has 42 RBI. In a 14-game span that ended this week, Murray had 20 RBI and went 26 for 54 (.481).

While Murray has been the AL's player of the week for the past two weeks, Singleton has been the prayer of the week.

Praying for a hit, that is.

In the Baltimore clubhouse, Mr. Slump and Mr. Streak sit only two lockers apart. It all started, for both Singleton and Murray, on Aug. 25. And it started as paradoxically as many a murder mystery.

On that date, the two Orioles left Seattle's tiny Kingdome after having amassed 13 hits and 11 RBI between them in three games.

Naturally, that wild weekend of slugging sent them both into slumps. That's the perplexing dynamic for many fine hitters. The hotter they are, the greater danger they face of an imminent collapse.

"We came home to Memorial Stadium and we were both probably home-run happy," said Singleton. "I'm pretty sure I was."

Singleton went two for 25, Murray three for 26 in eight games. All singles.

Oddly, this manageable minidisaster had a worse psychological effect on Singleton than Murray, because, in a sense, he had far more to lose.

Throughout his career, Singleton, traditionally a slow starter and fast finisher, had hoped for one year when he could put two hot halves together into one fabulous season that the baseball world couldn't ignore.

This was going to be the year Singleton went public. After a month, he was hitting .474 and had lit the sky with a 10-for-10 binge.

After his late August West Coast show, Singleton, hitting .337, not only had the chance to win a batting title, but saw the crowns for slugging, on-base percentage and even RBI within his reach.

How could Singleton, who in six Oriole seasons had averaged .320 for September and October, help but have high hopes?

For a proud but modest man, a rare star who has never sought attention but didn't mind it when it came, this looked like the MVP payoff, the showpiece to highlight a long, distinguished but distinctly underappreciated career.

How come it never works that way?

Murray, coming off a disappointing .259 first half, could harbor no great ambitions for his season. He just wanted what he really needed, a good-enough finish to justify his million-dollar-a-year contract and not embarrass himself.

On Sept. 4, Murray turned the corner.

Only in the last three games, going a mortal one for nine, has he cooled slightly.

"I'm not hitting the ball all that hard," said Murray, in a parody of a superstitious batsman. "The ball's just falling in. When I'm going good, I guess I wait on the ball, then attack it. I try not to move too quick. So, I guess I'm waiting pretty well right now."

Absolute end of discussion.

"Eddie's so loose you leave him alone 'cause you can only hurt him," said Sammy Stewart. "Kenny's lunging at the plate and overswinging and thinking too much and getting himself out. But it doesn't do any good to tell him that 'cause a great hitter like Singy knows it already.

"The problem is, he just can't stop doing it."

If Murray, never talkative, has lockjaw when he's hitting, then Singleton has reached the point where soul-bearing can only be therapeutic.

"This year, I've turned the calendar around. I usually have my slump early and my streak late . . . I feel like a field-goal kicker who keeps missing every kick just a little bit left or a little bit right," said the analytical, even-tempered Singleton.

"It starts by swinging just a little too hard when you're hot. Then, instead of getting home runs, it's fly outs. Then you start to tighten up and press to stay in that good streak. That makes your bat even slower. Your swing isn't short and quick and crisp.

"Once you're really in the slump," said the man who never thought he'd be an expert on the subject, "everything snowballs. The pitchers get ahead of you early in the count because you don't worry them as much. That second strike -- the one you really want to hit -- is either a great pitch or else you foul it back. Then, you've got two strikes and it seems like the umpires know you're in a slump, too, and the (ball-and-strike) calls get a little different.

"In the end, there's only one thing that's certain to hurt a hitter -- self-doubt. And when you're in a slump, that's all you have -- doubts."

This week, Manager Earl Weaver called Singleton for a closed-door conference.

"You look confused," said Weaver.

"I am," answered Singleton.

End of conference.

"Casey Stengel said he could tell when a hot hitter was going to turn cold and when a cold hitter was going to break out, and he'd change his lineup the day before it happened according to this magic feeling," said Weaver, sardonically.

"Well, I'm not that smart. I'll be damned if I can tell when they're going to go from one to the other, or flip-flop back again.

"I gave up trying to figure it out years ago. With guys like Frank Robinson, Lee May, Singleton and Murray, you ride high on the streaks and you ride out the slumps. Above all, you don't get smart and jerk 'em in and out of the lineup, 'cause then you don't get those nice numbers at the end of the year -- you know, .300, 25 or 30 homers and 100 RBI."

Murray and Singleton each began this season with career averages of .291.

Entering last night's game, after all the tumult they have endured this year, each had exactly the same batting average this season: .289.

The irony of baseball, or perhaps some would call it the moral of the sport, is contained in that infinitesimal, smirking, two thousandths of a point on a batting average.

No matter how a man struggles, exalts and suffers, he cannot escape himself.