The Pentagon strike again. Enough of the pattern of assingning active-duty officers to three-year tours as director of athletics at West Point, declared the Army Chief of Staff yesterday. Let's have some stability at the academy, some continuity.

With that, the chief, Gen. Bernard W. relieved Lt. Col. Len Marella, an active duty officers, of the post before he even assumel it officially. And named retired Maj. Gen. Raymond P. Murphy to the job, which Marella was supposed to begin in June. Murphy succeeds recently retired Col. W. J. (Jack) Schuder - and brings experience to the role: he was the Point's athletic director 1963-66.

Marella didn't have a big sports background. As for Murphy, he starts out even against Navy in football - his previous tenure, Cadets-Mids battled 1-1-1 . . .

Incidentally, that same tuneup game for Army this fall just before the two-week Navy builup: Cadets vs. Pitt, Nov. 12, and it's been moved to Giants Stadium in Jersey, at 70.000 double the capacity of Army's Michie Stadium . . . Not to be shut out, Navy's athletic director J. O. (Bo) Coppedge had an announcement yesterday, that Dale Strahm, defensive coordinator at Bowling Green in Ohio for six years, is joining coach George Welsh's football staff.Ohio Northern alum Strahm replaces Rick Lantz, whom Lou (Rolling Stone) Saban gathered for his new U. of Miami (Fla.) staff - before also enticing away Navy assistant Len Fontes, for whom Navy now must find a replacement.

Been wondering where's John Mahaffey, the young golfer who had the last two U.S. Opens all but won until the homestretch? He's been sidelined all season with an ailing elbow . . . Lee Trevino, practicing how to swing with a black that doesn't ache since his recuperation from December surgery on it, is waiting for the tour to shift from out West to Florida. "He is leaving for Florida within the next couple of weeks; he is about ready," said his wife, Claudia. Only thing is SuperMex's brand new, custom-made clubs disappeared at the Dallas airport in transit from Ohio to Trevino's home in El Paso. He put an ad in the paper offering a reward for them, commenting, "If they were stolen, I'll pay the guy a reward for stealing them" . . .

Then there is Steve Beman, 20, of Bethesda, who turned up on the $20,000 Pyramid daytime TV quiz show the other day - and won $10,000. Just might stake himself to a golf career, as he told the audience. After all, the game hasn't done badly by Uncle Deane Beman, the PGA tour commissioner. "Steve just got interested in golf in a major way in the past year," said Unk. "For now, he's just itching for the ground to thaw. Aren't we all?" Yes . . .

Or is it all downhill after partnering Adrienne (Maude's daughter) Barbeau on a game show? . . .

Bill Walton's achilles tendon still can't cut it, and he's out of the NBA. All-Star Game in Milwaukee Sunday. Who else but Don Buse - "yes," he stresses, "pronounce it Boozie" - to replace him on the West squad after winning the Filch-an-Ear award (steals vs. fouls) besides leading the league in thefts and assists . . . The West had an abundance of centers until Walton's injury, and Fightin' Kareem Abdul-Jabbar risked harm again Wednesday night in Buffalo. The Big Laker, who recently floored Seattle's Tommy Burleson, saying "you can only take so much," applied that philosophy when a fan heckled him unmercifully while L.A. was beating the Braves. Raced into the aisle behind the bench to confront the varmint, Kareem did, and folks had to break 'em up before heated words turned to worse . . .

The NFL management council andplayers association talked some more here yesterday to no conclusion about a collective bargaining agreement to replace the one that expired three years ago - maybe the high price of hotel coffee broke 'em up? But they'll try again Monday in New York - might be conducive, since that's Valentine's Day . . .

Making like sweethearts already are Fidel Castro and the New York Yanquis - er, Yankees. The Cuban premier, talking with Bill Moyers in a taped CBS-TV interview Wednesday night, capped a plug for restoration of trade and tourist commerce between his island and the U.S. with, "I'd personally want to see our Cuban baseball team play the New York Yankees." And a spokesman for the American League champs "very receptice, flattered," would go for a home-and-home series in Havana and New York, if the two governments approve . . .

Duane Bobick-Ken Norton in Mad Square Garden has been reset May 11.