At a Los Angeles Lakers practice in San Antonio last weekend, Bob McAdoo and Magic Johnson were playing one on one. McAdoo tried to post up Johnson.

"No, no," said Johnson. "You've got to go outside and handle it. You're not getting any cheap stuff. You've got to learn how to handle it, Doo. I'm going to give you a scholarship to my summer camp and teach you how to handle the ball. Then you might be as good as me."

McAdoo couldn't hold back his laughter, and he is smiling quite a bit these days as a key man in the Los Angeles drive to a National Basketball Association championship.

It has not always been this much fun, though. McAdoo has heard some awful things said about him during his roller coaster 10-year career. He has been called selfish, uncoachable, greedy, heartless, a loser.

This is the same player who also is one of the most prolific scorers in NBA history, a three-time scoring champion. Going into the current playoffs, he was tied with teammate Kareem Abdul-Jabbar for the best career scoring average in NBA playoff history (30.3).

"Some labels hurt more than others, but you learn not to let them affect you," said McAdoo. "People remember the bad things said about you more than the good things. You just hope that you're around long enough to show them the bad things aren't true."

In the span of eight months in 1979, McAdoo was traded from New York to Boston to Detroit for a total of five No. 1 draft choices. After a groin injury and an abdominal injury, he was waived by the Pistons, picked up by the New Jersey Nets and finally signed by the Lakers early this season as a free agent after Mitch Kupchak incurred a season-ending leg injury. As compensation, the Lakers gave the Nets a 1983 second-round draft choice and an undisclosed amount of cash.

"I knew I wasn't washed up, I was just injured," McAdoo said. "I knew some team would want me. I'm just glad it was the Lakers because I don't care much about anything anymore except winning the championship. And this seems to be the team to do it.

"That championship is the one thing I don't have . . . I'll do whatever I need to . . . get it."

Lakers Coach Pat Riley admits now that the Lakers were taking a chance signing McAdoo. "He had that reputation and we didn't know how he would fit in," Riley said.

Now he knows. McAdoo has fit in perfectly with the fast-breaking Lakers and is playing with more enthusiasm than ever. He also is starting to be just as effective as he was when he was one of the most feared scorers in the NBA in the mid-'70s.

In the playoff sweep of San Antonio, McAdoo, who doesn't start, averaged 20 points a game, shot 58 percent and also averaged more than seven rebounds. He made 12 of 16 shots and had eight rebounds in the series-clinching 128-123 victory Saturday in San Antonio. He averaged 14 points and 7.5 rebounds in the Phoenix series.

McAdoo joined the team Dec. 24 and missed 11 games late in the year with a torn calf muscle, but still appeared in 41 games and averaged 9.6 points.

"I knew I'd be a factor in the playoffs if I was able to get my shot and it's there," McAdoo said. "I feel as confident as I ever did and I'm having a lot more fun, too. This is the first time I've ever made it to the finals and it's an unbelievable feeling."

One by one, all of the bad labels are being shed.

"I liken Bob to Spencer Haywood," said San Antonio Coach Stan Albeck. "He was out of basketball and had a chance to think about just what it meant to him. And when he got the chance to come back, he was determined not to blow it. He's playing like a youngster and he is as valuable to that team as Magic, Kareem or any of them."

"I've never been on a team with this much talent," McAdoo said. "We're a hungry group, too. They got upset last year and I sat and watched them on TV, so I'm just as hungry."

Magic Johnson has become a big McAdoo fan.

"He's our secret weapon," said Johnson. "Whenever we need points we just go to Bob and say 'Hey, Doo, come get us a few' and he pops them right in."

McAdoo, 30, left North Carolina after his junior year and the Buffalo Braves made him the second player picked in the 1972 draft.

He always has been regarded as a great shooter, a man whose game revolves around his jump shot. He shoots it often and from virtually anywhere up to 20 feet from the basket. He has a unique, almost two-handed, release with little rotation of the ball. He has a 26-point career scoring average for 640 games and is a 50 percent career shooter.

McAdoo usually enters the game in the first quarter at power forward for Kurt Rambis. Then, when Abdul-Jabbar goes out for a rest, McAdoo moves to center. He also fits well into the team's running style because he is so mobile and fills a lane on the fast break like a small forward.

"He does exactly what we want him to do," said Riley. "He's never caused a problem and I doubt if he ever will. Bob McAdoo is back. It's just too bad he was ever away in the first place."