Baseball Commissioner Peter Ueberroth, declaring testing is a "huge deterrent" to drug abuse, apparently will make a new, all-out effort to win support of the players for his recently revealed drug control plan.

In an interview with Washington Post reporters a few days ago in St. Louis, Ueberroth's first since the major league owners terminated their 1 1/2-year-old drug agreement with the players last Tuesday, he said he is convinced testing will cut dramatically into baseball's drug problem.

"By testing, the military went from about 40 percent drug usage to single digits in one year," he said, adding that drug use among minor league players declined in the one season since a testing plan went into effect.

Ueberroth's plan, broached last month, includes unannounced testing three times a year, involving every player on every major league club. If a player should check positive in his urinalysis, he would be offered medical treatment and counseling. There would be no penalty, suspension or loss of pay, Ueberroth stressed.

The agreement the owners terminated did not include mandatory drug testing. That agreement has no connection to the new basic labor agreement negotiated last summer between the owners and players.

Donald Fehr, acting executive director of the Major League Players Association, was not available for comment yesterday. But Fehr said last week he was unhappy with the owners' cancellation decision and had previously expressed displeasure with Ueberroth's proposal.

"We have asked them questions they were unable to answer," Fehr said last week. "For instance, they said they wanted to begin using urinalysis. We asked them, 'What kinds of tests? What will you test for? Will there be any safeguards or guarantees?' They couldn't tell us."

Ueberroth, who said the abandoned plan, and drug programs in place in other sports, did not suffice, admitted his position with the players union was not strong. But he added: "I have not talked to a player who has told me not to do this. Everyone benefits by this. The players are under terrible pressures performing in such a difficult arena. So many people want to feed off them. I know I underestimated the problem when I took the job."

Nor does Ueberroth feel his no-retribution policy holds him in favor with some team owners and baseball fans seeking stiffer penalties in light of the recent Pittsburgh trial and conviction of dealer Curtis Strong during which seven present and past players testified about cocaine acquisition and use.

The commissioner did not indicate when or what actions he might take regarding the players who testified with immunity in the Pittsburgh case, or those players mentioned during the trial.

"I need to see the Pittsburgh seven and the 21 other players implicated or accused before I do anything," Ueberroth said. "There is still a hearing to go."

Ueberroth said an accurate assessment of whatever damage baseball suffered from the negative publicity generated by the Pittsburgh case could not be made until next year, although he did refer to it when discussing a decline in World Series television ratings last week.

"What we have here is more serious than economic issues," he said. "It's the most difficult problem in baseball and there are no easy answers."