During much of a spirited but otherwise meaningless exhibition basketball game Saturday night, it seemed as if Bill Walton never had been gone.

Walton was shorn of the familiar beard, and wearing a borrowed jersey, had number 23 on his back, not 32. But he still was in possession of the curly mass of red hair and open mouthed, intense gaze of concentration. He clogged the lane and took rebounds. He scored and played defense. Best of all, he said, his left foot was free from pain.

This was the foot that had experienced four stress fractures over two years and forced Walton's retirement from the San Diego Clippers in 1980 at the age of 27. It was expected to have been a permanent retirement. Yet, here was Walton at the Caesars Palace Sports Arena playing for a team of former UCLA players against a team of former Nevada-Las Vegas stars, and playing hard. Just like he used to.

"I'm tired," Walton said later at courtside. "But it's a good kind of tired. A very pleasant feeling."

Walton's numbers in what was known as the Community Roundball Classic 5 were 34 minutes played, 24 points, 21 rebounds and five blocked shots. UNLV, led by Chicago Bulls guard Reggie Theus and NBA journeyman Jackie Robinson won, 142-135.

The team of former Bruins had such notables as David Greenwood, Henry Bibby, Kiki Vandeweghe and Mike Sanders. The head coach was Walton, assisted by current UCLA Coach Larry Farmer, who didn't play. Of his coaching performance, Walton said, "I was pitiful."

He was less critical of the way he played, although he tired in the fourth quarter, when the Runnin' Rebels overcame a 10-point deficit.

"This is something I've been doing for a long time, but I haven't done it much recently," Walton said. "I got tired and I didn't handle the ball that well. At times, I wasn't sharp. But I had fun out there."

Walton was guarded primarily by one Eddie McLeod, whose listed height is 6 foot 5. Walton is 6-11.

Walton's timing was off on outlet passes; often the pass went to the wrong team. Still, he received good grades from the opposition.

" . . . I was very impressed," said Glen Gondrezick, of UNLV and the Denver Nuggets. "I didn't know what to expect after the long layoff, but he moved well. I don't think he's back 100 percent but he's on his way."

Walton, who recently finished his first year at Stanford Law School, said he has been playing pickup basketball games since April and enjoying his usual regimen of beach volleyball, bicycling and table tennis. It's not enough.

"There's a difference between working out and playing basketball with guys like Reggie Theus," Walton said. "It's a whole big difference. There's a shot clock and it was a 48-minute game. There's nothing that requires more, physically, than basketball."

Walton still is under contract to the Clippers, reportedly at $700,000 for each of the next two years. He appeared in only 14 games for San Diego after being signed as a free agent in 1979, and played his last game March 11, 1980. Walton's main success was with the Portland Trail Blazers, with whom he played for four years and led to the NBA title in 1977.

The problem was a stress fracture of the tarsal navicular bone in Walton's left foot. Before surgery, Walton had an unusually high arch that was not meant to take a pounding, much less the NBA.

"It was like a geologist tapping a rock with a hammer," said Dr. Ernie Vandeweghe, father of the Denver Nuggets' Kiki and Walton friend and adviser. "The rock doesn't smash, but after a repeated number of taps it cracks."

There was a lawsuit against Portland, charging negligence, that was settled out of court. There were three operations, the most significant one on Jan. 29, 1981. Walton says he remembers the date. The foot basically was rebuilt--the arch shaved and the pressure relieved.

Vandeweghe said a stress fracture can reoccur and Walton has been expressing a cautious outlook regarding a comeback. He said he does not yet know if he will attend the Clippers' preseason training camp in October because the foot must prove it can handle constant abuse.

"I've got to get in better shape," Walton said, "but that will come . . . with more playing. The big thing is not to do too much too soon. I have to keep in mind I have a long way to go.

"I have to keep focusing on the pleasures of the game and not force it. Top athletes in top condition, when things aren't going well, have to force it. I'm not in that situation."