Arthur Ashe is that rare athlete whose mind will allow him to drift quickly and successfully into the real world when his body says no more full-time tennis. Even now signs of transition are evident, his having to withdraw from singles in the Star tournament the week he takes a step into largely unexplored territory - television.

Somewhere between its usual staple of Chinese gymnasts and American weighlifters, ABC's Wide World of Sports Saturday will offer a 25-minute documentary called "Arthur Ashe in South Africa - Apartheid in Sports." It is a subject worthy of a thousand pictures and a million words - and television finally gets into the act.

As Ashe got lucky during the 10 days of research on the continent. There it is in the brochure for a soccer game allegedly involving racially mixed teams, "equal facilities for all." And there is Ashe - on camera - being denied the chance to buy tickets for five black youngsters.

"And the game itself (in Johannesburg) was an all-black team against an all-white team," he said, "even though the law allows three members of the opposite race on either side. I couldn't get anyone to talk about this on camera, but the reasons were so significant.

"I'd ask the whites, off the record, and they'd say there were no qualified blacks. I'd ask the blacks off the record, and they'd say that even if a white were qualified and wanted to play on the team they wouldn't allow it, because in doing so it would imply that there aren't three better black players.

"Imagine. Two diametrically opposite reasons for the same thing."

Having been born and raised in Virginia - "and sat in the back of the bus myself a few times" - Ashe still was at times startled and often saddened as he examined issues that included the withdrawal of so many black nations from the '76 Olympics.

"It's a psychological war," he said, "the Africans with the ingrained inferiority complex and the whites with an almost Don Quixote-like attitude, although for less noble motives. They see themselves as capitalist, anti-Communist idealists in the midst of black hordes of socialist Communist nations.

"And everyone is such a creature of habit. You see the Africans going toward the 'black' windows (at sporting events) and the whites going to the 'white' windows. People still don't trust themselves to try it out.

"When I was in line and being refused tickets by a guy who said, 'You'll have to go around to the other side' and, 'I'm just doing my job,' I was tempted to ask him if he'd ever heard of Freddie Prinz.

"But it wasn't the time for levity. It was saddening more than anything else. And I thought, 'Well, this thing is a hoax.'"

For the most part, Ashe said, he allows the film and the people to set the overall tone, and a bit of opinion at the end might be scrubbed in the editing that was taking place late yesterday. While Ashe was on a Maryland court testing his foot, word drifted down from New York that the piece would be cut by two minutes, so Joe Namath can tell us what it's like to play quarterback in Disneyland.

"This is the area I'd like to get into in television," Ashe said. "Frankly, all this 'Fine shot, now let's see it again on replay' stuff I can do in my sleep. And the piece Saturday is a way of testing, to see if the public is interested in sports journalism or strictly action-action."

When ABC signed Ashe, he was sitting with Roone Arledge, among others, and trying to determine his role with the network. Suddenly, Arledge asked about examing the South African system and Ashe said: "I was just about to asked that myself."

Whether it be a cry in the New York Times, to young blacks to spend two hours in the library for every hour at play or a defense, in The Washington Post, of Ilie Nastase. Ashe has a solid reputation for well-reasoned thought.

So, at age 34, has Ashe considered his athletic future?

"That's what I'm out here to find out," he said. "I'm not convinced that the flesh is unwilling, as yet, I think I can take it a while longer."