Managerial merry-go-round

''In today, out tomorrow,'' a good motto in the cleaning business, comes close to describing the tenure of today's major league manager. Since 1970 only one manager, Baltimore's Earl Weaver, has stayed put. By contrast, Billy Martin has hopped from Detroit to Texas to New York twice and now finally to Oakland.

Though the A's, Yankees, and Angels always seem to be breaking in new managers, keeping track of who's in the Texas Ranger dugout may be the league's hardest assignment. The Rangers have had nine managers since moving to Texas from Washington in 1972.

There's a saying that managers are hired to be fired. They are convenient scapegoats in a game where strategy decisions are easily second-guessed.Making their jobs all the more precarious are impatient owners, who shell out incredible sums for free agents and expect instant results.

Ousted managers, however, are frequently rehired by other clubs. Managers resurfacing with new clubs in 1982 are Joe Torre (Atlanta Braves); George Bamberger (New York Mets); Dick Williams (San Diego Padres); Bobby Cox (Toronto Blue Jays), and Pat Corrales (Philadelphia Phillies). Getting his first managerial assignment is Lee Elia with the Chicago Cubs.