The head of the Major League Players...

The head of the Major League Players Assn. said baseball club owners had fired the arbitrator in the midst of his hearing a dispute over free agents because they were unhappy with what was happening.

“It should be evident that the clubs and their commissioner (Peter Ueberroth) simply don’t like how the collusion case is going,” said Donald Fehr, the executive director and general counsel for the players’ association.

“So they have tried to fire the arbitrator and abort the trial, saying they would like to start all over again some other time, some other place, with some other arbitrator.”

Tom Roberts, who had been arbitrating a hearing into union charges that owners conspired to limit free agent movement last winter, was fired Tuesday by the Player Relations Committee, the owners’ labor arm.

Roberts, a Los Angeles attorney, struck down the drug-testing clauses in major league players’ contracts last week, holding that such clauses had to be negotiated through the union. Management said that decision had led to his firing.