Perhaps only the Philadelphia Phillies would, in their 100th anniversary season, become the first team in history to fire its manager in midseason while the club was in first place.

Somehow, it seems fitting that the franchise with the longest sustained history of failure would pick its centennial season to cashier a manager who was doing a creditable job and replace him with a 59-year-old front office executive who had managed only 80 games (33-47) in the last quarter of a century. Tonight he went 0-2 in his new term after a 7-3 loss to Houston.

In some senses, the canning of Pat Corrales here Monday is an almost prototypical example of how baseball organizations think, and how managers get fired. When the front office outsmarts itself, and when millionaire players don't perform to their proven ability, it's often the tough little manager who used to be a last-string catcher who gets left by the road to bleed.

These days, the Phillies seem to be a team that's traded itself into a corner and, now, has found a scapegoat.

The front office force who made the Phillies excellent in the last eight years has been 11-year General Manager Paul Owens--The Pope. When the Phillies won their first world title in 1980, he took many a well-deserved bow.

However, since then he's been in a slump.

Phillies President Bill Giles says, "There's no question about the talent. I think the chemistry might be a problem . . . There are a lot of former (sic) Hall of Famers down there. They may be over the hill . . . we'll find out."

Before this season, Owens gazed over the collection of famous oldsters he'd collected and called them "the best team I have ever assembled."

Corrales may have been a victim of that sentence. Once the brass has gone on record as believing that it, in its wisdom, has put together a great team, then heaven help the manager who has to live with its rosy miscalculations.

Many here in this hard-to-fool town suspect the talent that Giles and Owens have assembled is a larger part of the problem than "chemistry."

Last winter, the Phillies traded five for one with Cleveland to get Von Hayes, who now has 15 RBI in 228 at bats. Two of those five were gorgeous-fielding Manny Trillo, who's hitting .271 and started in the All-Star Game two weeks ago, and Julio Franco, a .280-hitting shortstop who's leading the Indians in RBI (50) while batting ninth and may be AL rookie of the year.

While Trillo and Franco cavort in Cleveland, Joe Morgan (.196) and Ivan DeJesus (.240) have been less than adequate here. Giles said flatly today that Morgan has "two or three weeks" to show that he isn't washed up before the Phillies call up Juan Samuel from Portland.

Don't mention other Phillies of '80 who have since departed in trades that now have a distinct aroma: Lonnie Smith (.312 in St. Louis), Keith Moreland (.298, 49 RBI with the Cubs) and Bob Boone (an '83 All-Star catcher as an Angel), plus hot prospect Ryne Sandberg (.270 with the Cubs).

Now Owens, the man who Philadelphia columnist Stan Hochman says "speaks quietly and carries a big swizzle stick," will be a living test case of the baseball equivalent of papal infallibility. He doesn't have too tough an act to follow. Corrales was almost the definition of "average."

In three years with Texas and two here, Corrales was long on macho and good with pitchers, but short on patience and psychology.

But he never expected to get the ax when his team was in first--even if it was only by a percentage point, even if his Phillies were just 43-42. Such a firing is a betrayal of baseball's unstated social contract.

The rest of this Phillies season will, to fans here, have a bit of a morality play dimension. Corrales was the guy who stood up to the millionaire players, benching them abruptly after bad games, telling them loudly that they weren't going to get him fired. If Pete Rose didn't like batting No. 2, or being rested or even taken out of the lineup for nine games in a row, then he could lump it.

For constrast, Owens is the man who'll put his judgment of talent on the line. He says he'll play proven stars like Rose, Morgan, Schmidt, Gary Matthews and Bo Diaz as long as they can stand. And his favorite youngsters, like Hayes and Bob Dernier, won't have to wonder about their status.

"Paul has a history of rejuvenating players, and he has an eye for talent. The Pope has a good teaching record. Because of his compassion and strength, for the job at hand, he probably has the wherewithal," says Tug McGraw.

"We (older players) have a built in motivation, but we haven't been havin' much fun. Sometimes, with everything that's going on, you forget to enjoy the game. That just gets burried so deep that you don't know how to bring it back to life.

"Every ship needs a captain. Somebody has to soak up the responsibility so that the crew can do its jobs. Maybe, this year, Schmidt, Joe, Pete and Matthews were feeling the burden of responsibility themselves."

"I want to find out who's playing and who wants to play," says Owens. "Handling players today is not easy, and it's no secret that this is one of the toughest clubs to manage. But, perhaps, I can reach them . . .

"I said all along it was going to be a dog race."

Whether the National League East proves to be a dogfight or a horse race, Owens and his hand-picked old guard will make their last run together.