Star outfielder Dave Parker testified today that he introduced an alleged cocaine dealer to his Pittsburgh Pirates teammates in 1979 and arranged cocaine purchases for players on other teams, including J.R. Richard, Steve Howe, Dusty Baker and Derrell Thomas, in 1980.

Under cross-examination on the fifth day of testimony in the cocaine-trafficking trial of Philadelphia caterer Curtis Strong, Parker, who said he used cocaine for seven years, identified Shelby Greer as the Pirates' major source of cocaine. Parker also said that, occasionally, he arranged through the team's traveling secretary for Greer to travel on the team's commercial flight to road games.

Greer brought cocaine with him on trips to Philadelphia and San Diego, for Parker and his teammates, Parker testified.

Defense attorney Adam Renfroe Jr. asked Parker: "As a result of your introducing Shelby Greer, the players went from the world championship to the bottom of the National League, isn't that correct, Mr. Parker?"

Parker replied, "That's a pretty strong statement, sir. I don't carry that burden because I don't take responsibility. Those relationships are ones that adults conduct with one another."

Greer, 29, of Pittsburgh, was one of six other men outside baseball who were indicted May 31 by a federal grand jury that investigated cocaine sales to major league baseball players. Greer, who is charged with 10 counts of trafficking cocaine, has pleaded not guilty and is scheduled to go to trial later this month.

Reached by telephone after court today, John Zagari, Greer's attorney, said: "My comment is that if David Parker, swearing under oath in federal court that these are the things that happened, I would have to assume that they are true."

Zagari also said he is trying to arrange a plea bargain for Greer.

Parker's cross-examination will resume Thursday. Renfroe is likely to inquire about the use of amphetamines on the Pirates. On Tuesday, Dale Bera testified that amphetamines were dispensed to other players by Willie Stargell and Bill Madlock.

After court today, Renfroe said he may call Stargell and Pete Rose to testify as defense witnesses. Lonnie Smith has testified he heard that Rose used amphetamines, which stimulate the central nervous system, when Rose played for the Philadelphia Phillies. Rose has denied the accusation.

By the time Parker, the National League RBI leader who also ranks among the top 10 in home runs and batting average this season with the Cincinnati Reds, had finished his four hours on the stand today, he had told of using cocaine himself from 1976 to 1982, of using it with at least 11 other players and of discussing with Strong the possibility that Smith was using too much cocaine.

As he was led through his history of cocaine use by U.S. Attorney J. Alan Johnson, Parker said he purchased the drug from Strong four times in Pittsburgh in 1981 and 1982.

Parker said he stopped using cocaine in late 1982 without undergoing any kind of rehabilitation. "It was a preference thing," he said. "I felt my game was slipping and I felt that was part of it. I felt my game was more important than cocaine. I have a daughter and I felt she was more important to me than cocaine. I wanted to get married, and that was more important to me than cocaine. It was a matter of priorities in my case."

Later, in cross-examination, Parker said his salary at the time was in excess of $1 million annually, with all but $300,000 deferred. Parker said his salary the past two seasons has been $800,000, plus incentive clauses depending on his number of at bats.

After court, Renfroe said Greer did not supply cocaine to the Pirates after the 1982 season, because the baseball commissioner's office "cracked down" and Parker was told "to stay away from" Greer. In New York, Richard Cerrone, a spokesman for Baseball Commissioner Peter Ueberroth, said, "We don't want to comment on anything that's going on in legal proceedings."

Parker, who played for the Pirates for more than a decade, signed as a free agent with the Reds after the 1983 season.

Renfroe has characterized the players who are testifying here with immunity from prosecution as "hero-criminals" and said his case would rise and fall on the credibility of the players, whom he referred to as "junkies" in his opening statement. Today, he showed inconsistencies in Parker's testimony in relation to his statements to the Federal Bureau of Investigation and to the grand jury.

By the time court was recessed for the day, Parker had described how he met Greer on a flight to Denver as the Pirates went to Japan for a series of exhibition games after beating the Baltimore Orioles in the 1979 World Series; of introducing Greer to then-Los Angeles Dodgers Thomas, Baker, Howe and Pirate Lee Lacy (now with the Baltimore Orioles) in 1980 to arrange a purchase with Greer in a Pittsburgh hotel, and of arranging at Three Rivers Stadium for Richard and Enos Cabell, then teammates on the Houston Astros, to buy cocaine from Greer.

Parker testified that he used or shared cocaine with the following players, either as a Pirate or playing winter baseball in Venezuela: John Milner, Dale Berra, Rod Scurry, Al Holland, Lacy, Cabell, Baker, Thomas, Manny Sarmiento, Eddie Solomon and Howe.

All the players except Thomas, Baker, Solomon, Howe and Sarmiento testified with immunity before the grand jury. Berra and Cabell were previous government witnesses here, and Milner, Holland and Scurry are on the prosecution's list of potential witnesses.

Parker said he did not introduce Greer to his Pirates teammates as a cocaine dealer, but as a man dealing in gas and oil investments. But Parker conceded that neither he nor any of the other Pirates had invested in oil and gas with Greer.

Finally, after Renfroe read grand jury testimony in which Parker said, "It came to a point Shelby was selling directly in front of the park after games," Parker said. "I introduced Shelby Greer to the whole team."

At one point, the prosecutor asked Parker if he and Strong had talked about Smith, the Kansas City Royals outfielder who was the first player to testify in this trial.

"We were talking about cocaine. We also were speaking in terms of its effect on different people. And he brought up the fact he was sending Lonnie Smith virtually a quarter ounce (seven grams) a week . . . A lot of people, I felt, were out of control, from some of the guys I was around."