A cocaine-trafficking trial that has become the biggest embarrassment for major league baseball since the Black Sox Scandal following the 1919 World Series enters its third week Monday in U.S. District Court here.

By the end of the second week, seven players had spoken in detail about hundreds of purchases of cocaine from the defendant, Curtis Strong, and others, including sales arranged between players, although all those testifying say they never made a profit on a sale. Reputed cocaine dealers had access to the Pittsburgh Pirates' clubhouse, testimony has alleged, and one sale was said to have been made there during a game.

There was testimony that Willie Stargell and Bill Madlock had dispensed amphetamines, or stimulants. Even the name of Willie Mays, one of the greatest players in the history of the game, did not go unsullied. John Milner, a former teammate of Mays' on the New York Mets, testified he found liquid amphetamine in Mays' locker at Shea Stadium.

These details emerged after opening statements by defense attorney Adam Renfroe Jr. that the players, whom he portrayed as hero-criminals, and not Strong and the six other men indicted here May 31 were the real drug dealers.

Thursday, after National League RBI leader Dave Parker of the Cincinnati Reds completed two days of testimony in which he told of introducing an alleged cocaine dealer to his then Pirates teammates, of arranging cocaine purchases for players from three teams in 1980 and of making arrangements for his "primary source" to travel occasionally on the team's commercial flight to games, Renfroe said:

"Dave Parker said enough things that, if he didn't have immunity, he'd be in jail for 150 years."

In his opening statement, Renfroe told the jury he would be speaking like a prosecutor. And, indeed, in six days of cross-examining seven player-witnesses, Renfroe prosecuted baseball and the players.

The players, especially Keith Hernandez and Enos Cabell, have shown a reluctance to name names, and no one in baseball has been willing to estimate how many current players are addicted to drugs. The commissioner's office is not commenting at the moment. Only Renfroe is talking: "I don't think all ballplayers are addicted. Forty percent are addicts, and 90 percent have used drugs."

One pattern emerged throughout the testimony by seven players, who have implicated about 20 other current and former major league players as cocaine users and about another dozen as users of amphetamines.

These players have time and money on their hands and most have done little else since puberty except play baseball. For whatever reason, Parker wasn't even able to read his own grand jury testimony to the jury. Renfroe, who has shown open scorn for the players, gladly volunteered to read it for him.

Lonnie Smith of the Kansas City Royals said he started using cocaine when he was in Venezuela, where the drug was plentiful. Cabell of the Dodgers and Dale Berra of the Yankees said they used their greatest amounts of cocaine when they were on the disabled list. When Jeff Leonard of the San Francisco Giants testified his annual salary was $900,000, there was a collective gasp from the spectators.

Except for John Milner, who was released by the Pirates in spring training in 1983, the players said they stopped using drugs either because of pressure from management, fear of getting caught or a concern that their skills were deteriorating too much.

Milner said he stopped using drugs in 1984 because, "It's a rich man's high. I couldn't afford it. I have to take care of my mother and my sister." Milner, 35, testified that his highest salary in 11 major league seasons was $200,000 and that he has been unemployed since the Pirates released him.

Some of the names came out during direct examination by U.S. Attorney J. Alan Johnson and his assistant, James Ross. But many of the most interesting details and revelations were elicited through the histrionic efforts of the flamboyant Renfroe, 35, a former assistant district attorney in Philadelphia.

Renfroe's disdainful attitude toward the players is part of his strategy to prove that his 38-year-old client is "a scapegoat" for them. His style has rankled the judge, frustrated the prosecutors and left the spectators occasionally laughing.

Even in high school in the Germantown section of Philadelphia, where he and Strong grew up together, Renfroe apparently was flamboyant. Renfroe was an all-public school flanker on the football team and played second base and right field in baseball. Strong said Renfroe, who wore white shoes with white tape, was "the only flanker I've ever seen who never got dirty."

So far in the trial, with Renfroe saying the first witnesses the defense will call will be more ballplayers -- and speculation centering on 20-game winner Joaquin Andujar, Willie Stargell and Pirates Manager Chuck Tanner -- the government has produced five players who testified they bought cocaine from Strong in the Western District of Pennsylvania, accounting for most of the 16 counts against the defendant. "Major league baseball is not on trial here," Ross said in his opening statement. "Curtis Strong is."

But Renfroe's case hinges on discrediting the testimony of the players, so that the trial becomes a matter of their word against his. And Renfroe hopes the jury will sympathize with Strong. Whether the jury does that may not be known for another week or two.

Renfroe graduated from Howard University Law School and has a graduate degree from Harvard in city planning. His Philadelphia law firm is called Renfroe and Renfroe. His sister Patty, who graduated No. 1 in her class from the University of Pennsylvania Law School, is the other Renfroe. "I'm the PR man and the front man," he said after court one day this week. "She's the brain."

Thursday, leaving the court room, Renfroe spotted a 16-year-old Pittsburgh high school student who had to ask Berra twice for an autograph. The boy is covering the trial for his school newspaper.

Renfroe put his arm around the boy's shoulder, smiled and said, "What do you want to know?"

First, the youth wanted to make sure that Renfroe wasn't going to call his idol, Carl Yasztremski, to testify. Once assured of that, the boy wanted to know what the long-range effect of this trial might be.

"What happens in the trial will last a lifetime," Renfroe said.

Clearly, that is not courtroom hyperbole.