INDIANAPOLIS, AUG. 20 -- The U.S. Olympic Committee's medical chief said today there were "several" athletes using a drug to hide steroids, not just two or three as Pan Am officials said.

Dr. Robert Voy said the athletes were from more than one country.

"I kept seeing this statement that there were two and I knew differently," he said. "When I asked the lab people they just said several."

Voy said he did not know the specific number involved.

U.S. hammer thrower Bill Green, a silver medalist, and five other athletes were disqualified Monday after failing drug tests.

On Tuesday, Pan American Sports Organization officials announced that two or three athletes were using probenecid, a drug that can hide steroids in tests.

But no action was planned against the athletes because probenecid, commonly used to treat gout, is legal in international competition.

PASO officials said none of those disqualified used the masking drug, which enables the body to hold steroids longer so they don't show up in tests. Voy said Dr. Manfred Donike of West Germany has told him he will recommend that probenecid be added to the International Olympic Committee's list of banned substances.

"We'll make a recommendation either to support his motion or we'll make a recommendation of our own," Voy said.

The recommendation will be made at an IOC medical commission meeting Oct. 1 in Moscow.

Voy said this would not be the first drug banned because it helps athletes hide other drugs in their system. He said diuretics, added to the list in July 1986, can dilute the urine and help athletes pass drug tests, as well as help athletes drop weight rapidly.

"That precedent has already been established," he said. "If we're going to have this program, we have to add these drugs to the list.

"But I don't think there are a bunch of them."

The U.S. baseball coach says his players must forget the tense victories over Cuba and Puerto Rico at the Games and tend to more immediate matters -- Canada.

"I'm sure we're the ball club they want to play," said Coach Ron Fraser, whose team meets the Canadians in Friday's semifinals. "They have a lot of confidence against us. We have a great deal of respect for Canada."

The U.S. team, 7-0 and the top seed in the medal round, faces a Canadian team that won three of five from the Americans in a pre-Pan Am Games series. And in the Games' opener, Canada led by four runs before losing.

"They just seem to play us well," Fraser said. "Our scouting has been very good. We have a good line on how to play these people, but I'm sure they have some good scouting on us, too."

Cuba, seeking its fifth straight Pan Am title, takes a 6-1 record into its semifinal game against Puerto Rico (5-2). The lone Cuban loss came when Ty Griffin hit a two-run homer in the bottom of the ninth to carry the United States to a 6-4 victory.

Cuba's Pablo Abreu threw a one-hitter to drop Puerto Rico, 1-0, in the preliminaries. In Puerto Rico's 4-0 loss to the United States, the game was scoreless before the U.S. team struck in the 11th inning.

The top two finishers in the Games, excluding Cuba, qualify for the 1988 Olympics. Cuba has already qualified since it is the defending world amateur champion. If the Americans win Friday they are assured a spot in Seoul, South Korea.

A major concern for the U.S. squad has been hoopla surrounding the victory over Cuba.

"It was the kind of ball game that should've happened in the last game," Fraser said. "There's been a lot of media attention on it, but I think the players after last night's game {with Puerto Rico} have forgotten about it."

Joe Slusarski (3-0), of Springfield, Ill., will start for the Americans. The right-hander has a 0.64 ERA (one run in 14 innings) and 10 strikeouts.

"He's the kind of pitcher who always has good control and he has velocity," Fraser said.