NEW YORK -- Three more of the 22 umpires who lost their jobs during a failed mass resignation in 1999 were rehired.

Paul Nauert, Bruce Dreckman and Sam Holbrook began working minor league games this week, the commissioner's office said Thursday.

Baseball has rehired eight of the 22 umpires dropped following the mass resignation three years. Four others were allowed to retire with back pay.

The three brought back Thursday had been out of baseball since Sept. 2, 1999. They replace Charlie Williams, Dan Morrison and Rocky Roe, who left the major league staff during the season on disability caused by on-field injuries.

Also Thursday, the umpires' union kept up its fight with owners. Angry that management has refused to provide information on a computer system that analyzes balls and strikes, the union filed a demand to have the American Arbitration Association resolve the dispute.

"We need to know what it can do and what its capabilities are, and then how its capabilities can translate to baseball,'' said Joel Smith, a lawyer for the World Umpires Association.

Thursday's rehirings bring the major league staff to 67, one short of the minimum set in the union's labor contract.

The mass resignation was orchestrated by Richie Phillips' Major League Umpires Association as a bargaining tactic, but it collapsed when many American League umps refused to go along.

The MLUA then filed a grievance, and in May 2001 arbitrator Alan Symonette told baseball to rehire nine of the 22. That decision was upheld last December by U.S. District Judge Harvey Bartle III, who in addition ordered new arbitration hearing for Nauert, Dreckman and Holbrook.

The WUA currently is fighting with owners over the computer tracking system. Umpires filed a grievance against owners on July 19, claiming the refusal to provide information on the system violated their labor contract.

Rob Manfred, the owners' top labor lawyer, did not return a telephone call seeking comment.

Umpires claim the computer system does not accurately track pitches, especially breaking balls.

The July 19 grievance was filed a day after owners sued the union in federal court, asking for an order that its attempt to discipline John Hirschbeck, the union head, was not subject to arbitration. Owners asked for a permanent injunction preventing the union from taking the dispute to arbitration.