Former National League batting champion Keith Hernandez testified today that cocaine use by major league baseball players was prevalent in 1980 and that he told a grand jury he believed 40 percent of the players were using the drug then.

By the end of today's testimony in the cocaine-trafficking trial of Curtis Strong, a former caterer for the Philadelphia Phillies, six more players had been named by Hernandez and Enos Cabell, the other player who testified today, as also having used the drug. These included former pitcher J.R. Richard and current National League runs-batted-in leader Dave Parker.

Under direct examination by U.S. Attorney J. Alan Johnson, Hernandez said he first used cocaine in 1980, stopped in 1983 and never considered himself addicted to the drug. He said he was able to rehabilitate himself.

Asked by Johnson what the extent of cocaine use was in pro baseball in 1980, Hernandez replied: "I think it was the love affair, the romance with the ballplayers. It was prevalent with ballplayers. I don't know the percentage, but it was widely used in major league baseball."

But Hernandez, who was traded by the St. Louis Cardinals to the New York Mets in June 1983, said cocaine use by the players has declined since four members of the 1982 Kansas City Royals were convicted in 1983 of possessing cocaine and served jail sentences.

The third day of testimony in this trial that offers a rare public glimpse into the use of illegal drugs by professional athletes is to begin at 9:30 a.m. Monday. At that time, Cabell of the Los Angeles Dodgers is scheduled for cross-examination.

Cabell testified he had used cocaine with former Houston Astros teammate Richard; Parker, who left the Pittsburgh Pirates for Cincinnati after the 1983 season; Jeff Leonard, a teammate of Cabell at Houston and San Francisco; Al Holland, a former Giant, Phillie and Pirate now with the California Angels; and Dick Davis, formerly of the Phillies and now playing in Japan.

Today's first witness was Hernandez, who said he recently signed a five-year, $8.4 million contract with the Mets. He said Bernie Carbo (no longer in baseball) had introduced him to cocaine during the 1980 season. Hernandez numerous times said he could not recall the names of players with whom he had used cocaine. Nevertheless he did name Lary Sorensen, now with the Chicago Cubs; Lonnie Smith, who testified Thursday, and Joaquin Andujar, who was named by Smith. Andujar, through the Cardinals today, declined comment.

Smith, Hernandez, Cabell, Parker and Holland were among at least 12 current or former major league players who testified with immunity before a federal grand jury here that indicted Strong and six other persons from outside baseball May 31 after investigating cocaine sales to major league players for 13 months. Three of those six have plea-bargained and are awaiting sentencing.

Hernandez testified that he bought cocaine from Strong "three to five times" in Philadelphia in 1982 and had Smith buy him cocaine in Pittsburgh "five or six times" in 1982 and 1983.

"Why did you ask Lonnie Smith to get you cocaine (in 1982)?" Johnson asked.

"I figured major league baseball was getting aware of the cocaine problem," Hernandez said. "It was pretty apparent they were. I wanted to be safe. I didn't want to be seen around Curtis. I figured he was being watched."

Early in his cross-examination, Adam Renfroe Jr., the defense attorney, tried to establish the fact that Hernandez was a drug addict.

"Isn't it true, once an addict, always an addict?" Renfroe asked.

"I wouldn't know," Hernandez answered.

"You once were an addict, weren't you?" Renfroe responded.

"I don't believe so," Hernandez countered.

Hernandez's team, the Mets, issued a statement saying they "regret the pallor that this whole matter casts over major league baseball."

Earlier Hernandez said, "I wasn't using it every day. But it got to the point I realized I had to get away from it . . . The more you do it, it gets away from you, and it's not as enjoyable as when you first did it. It dominates you. It keeps you up, and you have an insatiable desire for more."

Hernandez said the impact of seeing Smith walk into the team's clubhouse too "strung out" to play in June 1983 had a big impact on him.

Hernandez was traded to the Mets about a week later, but he denied that his suspected use of cocaine was the cause of the trade. However, Hernandez related, at a team meeting in either late April or early May of 1983, the season after the Cardinals won the World Series, Manager Whitey Herzog said he suspected three players as being cocaine users.

"He said if they didn't come forward, he would trade or suspend them, I forget which," Hernandez said. "No one came forward. Nothing happened."

Hernandez said he has not used cocaine since joining the Mets.

(In 1980, he was coming off his peak, co-MVP 1979 season in which he hit .344 with 105 runs batted in. He hit .321 with 99 RBI in 1980 and, year in and year out, has consistently continued to rank high in productivity on the field.)

When Hernandez finished testifying, he flew to Los Angeles to rejoin the Mets, who had a game last night with the Dodgers. He missed Wednesday's game in San Diego.

Taking the stand late in the day, Cabell told of purchasing cocaine from Strong six times between 1979 and 1984, including twice in Pittsburgh, in the Western District of Pennsylvania, where Strong is charged with 16 counts of trafficking the drug.

Cabell testified that Davis had introduced him to Strong in Philadelphia in 1979. Smith testified Thursday that he had met Strong through Davis in 1981.

Under direct examination, Cabell gave few details about using cocaine with the other players he mentioned. He said that when he was with the Astros, Parker, then with the Pirates, came up to his room in Pittsburgh one night and shared cocaine with him.

Cabell said he stopped using cocaine in May 1984. But he said that was two years after Tigers Manager Sparky Anderson called him into his office shortly after his trade to Detroit. "He said people had told him I was using cocaine and he asked me to stop," Cabell said. "I stopped almost, not totally."

Asked by Assistant U.S. Attorney James Ross why he stopped completely, Cabell replied, "Everybody was coming down on the players about using it, and I had to stop. I was getting older, and I had too much to lose."