Though formal voting on a proposal to test major league ballplayers for illegal drug use was incomplete, several teams yesterday closed ranks behind their union and said the plan must be negotiated by the players association before they would participate.

None of the teams endorsed baseball Commissioner Peter Ueberroth's voluntary testing proposal without a requirement that it be cleared by the players association, which represents the 650 major leaguers. However, some players indicated they might agree to a form of blanket testing.

"I don't want to make it sound like this is something we're totally against," said Chicago Cubs player representative Keith Moreland. "But . . . the commissioner did say (the proposal) wouldn't go into effect until 1986, so there is plenty of time for us to sit down and work something out on a voluntary basis."

San Francisco Giants player representative Jim Gott said he would submit to testing. "I don't want anybody to question whether I'm using drugs because I'm not, and I'm out there giving 100 percent every day."

The Cincinnati Reds' Dave Parker, who recently admitted using drugs over a six-year span during testimony in a cocaine trafficking trial in Pittsburgh, said he favored Ueberroth's voluntary drug testing proposal -- as long as the players union was involved.

"I wouldn't mind being tested for drugs and I don't think there's a guy in this clubhouse who would mind," Parker said. "But I would favor that the program be administered under the guidance of the players association."

Ueberroth sent letters Tuesday to all major league players asking each to agree to be tested for illegal drug use three times a season. Each player was to be given a card to sign to indicate that he agreed to the testing, and Ueberroth directed each team to collect the players' responses by Friday.

Players on some teams, like the Seattle Mariners and Kansas City Royals, decided not to vote until the proposal was negotiated with the players association.

The Atlanta Braves, in a clubhouse meeting in Cincinnati, returned all their response cards blank. The team's player representative, Bruce Benedict, said the team did not agree or disagree with Ueberroth's proposal but did not vote because they had not been informed of the details of the testing.

Gene Orza, associate general counsel to the players union, said yesterday the "overwhelming weight of expert medical literature is that testing is not a solution because it necessarily establishes in the minds of those being tested a potentially coercive atmosphere, and a coercive atmosphere is not conducive to eradicating whatever problem there might be."

Orza also called the players' support of the union "predictable. We could have told him (Ueberroth) that would happen."

Meanwhile, in Pittsburgh, the second federal court jury in as many weeks deliberated the fate of a Pennsylvania man charged with selling cocaine to major league players. The jury, in its first day of deliberations in the case of Robert (Rav) McCue, failed to reach a verdict after 7 1/2 hours and adjourned for the night. It will resume work today.