The Louisiana Superdome, so eager so recently to house major league baseball, is on the verge of losing big league basketball: New Orleans Jazz brass blew into Salt Lake City yesterday to the tune of "When the Saints Come Marching In."

The Salt Lake Saints, that is, into the NBA, that is.

Not only did Jazz attendance slack this year to a 9,000 average in the Dome-little wonder with Pete Maravich hurt and the team posting the league's worst record, 26-56.

But worse, say the Jazz owners, has been the hassle with arena management over dates. Partners Sam Battistone and Larry Hatfield said in Utah that bookings in connection with Mardi Gras, conventions, etc., would deny the team use of the Superdome for up to five weeks at a time, and they can't live with that.

A Dome spokesman said adjustments already had been made to assure the basketball team seven home games a month, but Hatfield announced that the Salt Lake City Area Chamber of Commerce would be launching an NBA season-ticket campaign real soon.

And the Jazz owners will be meeting today in New York with NBA Commissioner Larry O'Brien to discuss moving the 5-year-old operation into the 12,000-seat Salt Palace.

The Utah Stars of Salt Lake folded out of the ABA in 1975, before part of the ABA folded into the NAB-but if the sport is reborn there, the city's Chamber of Commerce president, publisher Wendell Ashton of the Deseret News, owned by the Church of Jesus Christ of Latter-day Saints, recommends the team be called . . . the Saints. Or would that be rubbing it in on a bereaved N'Orleans left with one major club, the NFL Saints?

"I wish amateur athletics didn't trancend into politics, but unfortunately they do," sighed the Boston marathon's director, Will Cloney, in reporting that five South African entrants have been disqualified from the 6,800-person field that grinds it out Monday.

Cloney approved applications from the five last week, only to receive notice from AAU headquarters in Indianapolis instructing him "not to permit (them) to compete in the race under penalty of disqualifying all the competitors from future international events." The AAU in turn took its cue from the International Amateur Athletic Federation . . . And the vice premier of the Soviet Union, Ignati Novikov, has been going around to Madrid and places declaring that countries having sports contacts with South Africa and Rhodesia would be excluded from the 1980 Moscow Olympics. Ah, transcendence into politics . . .

The Boston marathon could fade into insignificance for the Rodgerses and Shorters of the world, after the '80 Olympics, if a promised Friday the 13th announcement here develops as advertised-a capital "Superthon" hinted to be a golden end (beginning?) of rainbow for the kings of long distance . . .

Indianapolis, again: Indy Motor Speedway officals were still waiting, at last report, for the first of the many-splendored Championship Auto Racing Teams rebels to enter their May 27 classic, the 500.CART continues to demand various concessions from the U.S. Auto Club, conductor of the Indy these many years, and deadline for entries is near-must be in the speedway or USAC office by 5 p.m. Friday or postmarked by Sunday.

Pat Patrick, president of the dissident owners and drivers, including most of the big names except A. J. Foyt, who joined but then left CART, indicated the breakaway organization might stage its own race on the same day if its demands for more control aren't met. Speedway prez Joe Cloutier says they'll chance it, won't yield.

CART seeks hike in turbocharger boost level.

National letter-of-intent time for college-bound basketballers arrived yesterday and, no last-minute surprise, Kentucky Coach Joe B. Hall flew (over Three Mile Island) to Lebanon, Pa., to sign 7-1 Sam Bowie-who set up ceremonies in the hospital where his sister Shelly, 16, is recovering from an appendectomy. Kentucky also signed its two other intended from the Capital Classic-Dirk Minniefield and Derrick Hord-while 6-8 Clark Kellogg of Cleveland, who upstaged Bowie in Cap Centre and ranked among top five front-court prospects anywhere, said sorry, Michigan, he's going to Ohio State. And make his home arena the one where he scored a record 51 points (of St. Joseph High's 65) in the state final loss to Columbus East.

Paul Blair, opening-day right fielder for the N. Y. Yankees, a distinguished performer in playoffs and World Series for both the Bronxies and the Baltimore Orioles who had him in his prime, has been shoved off the New York roster. Club has 10 days to deal him or he becomes a free agent. Would the Orioles, hard up for outfielders who can catch and throw the dern baseball, give an old buddy, superfielder Blair, a call? CAPTION: Picture, Bill (Spaceman) Lee of the Expos puts heart, soul and hair into pitch. AP