On the eve of the opening of training camp at Fort Meade, Bullet Coach Gene Shue said yesterday that second-year man Frank Johnson will be the starting point guard and veterans John Lucas and Kevin Porter will be competing for the backup spot. The loser probably will be cut or traded.

"We won't keep three small guards," said Shue. "There may be some contractual problems with both Kevin and Lucas, though, in terms of guarantees that may play a part in the final decision. I'm not sure yet. But there just isn't room for three small playmakers. The job belongs to Frank right now, and one of the other two will have to beat him out. Frank stepped in last year and did the job, and so it's his now."

Lucas was the starter at the beginning of last season after coming to the Bullets in a trade with Golden State. His problems with cocaine came to light during midseason and by the end of the year, he was not playing much.

Lucas said earlier this week he is a "new man" and is eager for camp to begin. He also vowed to win back the starting job.

Porter tore his Achilles' tendon in training camp last year, which prompted the Bullets to acquire Lucas. Porter says he simply wants to be able to play again.

"We do have a question mark at guard with an assortment of problems," said Shue. "Porter is coming off a serious injury and Lucas has his on-and-off problem.

"At the other guard spot, Kevin Grevey is still bothered by the groin injury that he got last year. He was inactive most of the summer and we don't know what he'll be able to do early in camp. That makes that spot wide open."

Shue said he will stress defense again this season, but added, "We're going to try to be a little more sophisticated" on offense.

Shue also is concerned about the other teams in the Atlantic Division, all of whom have made significant changes in personnel. Moses Malone is in Philadelphia, Len (Truck) Robinson is in New York, Darryl Dawkins and Phil Ford are in New Jersey and Quinn Buckner is in Boston.

"A lot of teams are going out and spending large amounts of money for players," Shue said. "I don't believe in it, but the teams we have to beat apparently do. There's no question that money is an important factor in winning. It disturbs me because we're trying to do things in a businesslike way, and on the surface it looks like we're falling behind."

They'll fall further behind if Grevey is not healthy. He was the team's third-leading scorer last year with a 13.3 average, his lowest in five seasons. Grevey suffered the injury in a game at Chicago April 9 and never fully recovered.

If he is healthy, Grevey will have the inside track for the guard spot opposite Johnson. But Don Collins and Billy Ray Bates, a former Portland Trail Blazer who was signed as a free agent yesterday, have a chance to start.

The Bullets signed another free agent yesterday, 6-foot-7 forward Keith Herron, formerly of Mackin High School. Herron played at Villanova and for Atlanta, Detroit and Cleveland in the National Basketball Association.

Herron, 26, averaged 13.7 points in 80 games for Detroit in 1980-81 and 2.8 points in 30 games with the Cavaliers last season. He became a free agent at the end of last season and the Cavaliers did not offer him a new contract.

Twenty players are expected to attend the first of the two-a-day practices today at 9 a.m., including all 13 veterans on the roster last season.

General Manager Bob Ferry said he didn't plan more personnel moves right away unless the right deal were presented.

"For this stage of our development I'm happy with our personnel, but I'm not satisfied," he said.

The first of six Bullet preseason games will be Oct. 11 at Atlanta. The regular season starts Oct. 29 at Indiana.