Running back Alonzo Highsmith, the No. 3 choice in this season's NFL draft but as yet unsigned by the Houston Oilers, won a preliminary ruling from a circuit court judge in Dade County, Fla., that he is a free agent because the Oilers and other NFL teams illegally engaged in price-fixing to hold down his market value.

In papers made public yesterday, Judge John Gale issued a temporary injunction Saturday night without notice or opposition, allowing Highsmith to sign with any of the NFL's 28 teams and enjoining the league from preventing any team from negotiating with the former University of Miami standout or from punishing any team for negotiating with or signing him.

Any team that signs Highsmith would not have to pay compensation to the Oilers or give Houston the right of first refusal to match an offer, under the finding.

After reviewing Gale's preliminary finding, the NFL's antitrust expert, Washington attorney Paul Tagliabue, said last night that the league would file a motion in Dade County court to dissolve the injunction, "Because state court has no jurisdiction in this case and because the case is without merit," Tagliabue said.

"The most significant thing," Tagliabue said, "was the papers were filed at 6 o'clock and the judge signed them at 6:10."

Tagliabue said that the NFL Players Association had agreed to conduct the college draft until 1992 even though no collective bargaining agreement exists at this time. He also said that the U.S. Supreme Court, in the Curt Flood case, set the precedent for the state courts having no jurisdiction in this type of case.

Houston General Manager Ladd Herzeg said he would not comment on advice of his lawyers.

Highsmith is one of four first-round draft choices who have not been signed this season. The others are linebacker Cornelius Bennett, the No. 2 overall pick, by the Indianapolis Colts; quarterback Chris Miller, by the Atlanta Falcons and quarterback Kelly Stauffer, by the St. Louis Cardinals.

Those players might join Highsmith's suit, according to a source in the NFLPA.

In his preliminary finding, Gale said the injunction was granted without notice because "the owners, general managers and personnel of some but not all defendant teams are constantly communicating among themselves and with the NFL Management Council regarding the salary structure maintained by the price fixing conspiracy in the NFL. Extreme pressure is placed on any team which attempts to break out of the lock-step salary parameters set by the conspiracy."

Robert Fraley, Highsmith's attorney, told The Boston Globe that Highsmith was not attempting to test the NFL draft, but only attempting to get a fair contract this season (the Oilers have offered him $2.4 million for four years). Also, Fraley said Highsmith waited for the recent 24-day players strike to end before filing. "He didn't want to cross the picket line," Fraley said, "so he waited for the strike to be over before he went to court."