The National Football League Players Association won another legal battle over pension funding yesterday when a six-person federal jury in Baltimore decided that the NFL's three-man management trustee board must contribute more than $25 million in back payments and interest.

NFL attorneys said they would appeal, although they pointed out the disputed money has been in an escrow account since an earlier court order to pay it almost two years ago.

The complex case began in late 1987, shortly after the last collective bargaining agreement between the players and owners expired and is the latest in what is already the longest-running and most bitter labor war in the history of American sports.

At issue is whether or not the owners could decrease payments to the pension fund. The owners had agreed in the 1982 labor agreement to put $12.5 million a year into it.

However, those payments were based on them being tax deductible, and when the Internal Revenue Service ruled in 1987 that all the payments were not deductible the NFL, saying the investments were doing better than expected, unilaterally cut back the payments.

With the money in escrow, John Jones of the NFL Management Council said last night that the league had always intended to put the $25 million into the fund.

"What we wanted was to put the money in some different areas," he said, so it would be deductible. "We were never trying to withhold the money."

The NFL wanted to change the way it made the payments, but that could only have been done during collective bargaining, something that fell apart during the 1987 strike.

The NFLPA now says it's no longer a union and apparently will communicate with the owners only in the courts.

The pension fund was managed by a six-member board, its representation split evenly between players and management. When the owners cut back payments in late 1987, the three player trustees -- former Chicago Bear Dan Jiggetts, former Kansas City Chief Tom Condon and former union head Ed Garvey -- sued the three management trustees: Phoenix Cardinals owner Bill Bidwell, Minnesota Vikings general manager Mike Lynn and former New York Jets president Jim Kensil.

U.S. District Judge Joseph C. Howard said the conduct of the trustees was "extraordinary" and that he would look favorably on requests for injunctive relief.

Joseph A. "Chip" Yablonski, a lawyer for the players, said he would seek a one-third increase in pension payments to players and that the minimum playing time for inclusion in the pension plan be reduced from four seasons to three.

He said he would also ask that workers' compensation no longer be deducted from pension payments and that the owners pay all attorneys' fees.

The NFLPA probably will ask that management of the fund be taken away from the management trustee team, since making pension plan decisions can be a conflict of interest for top management executives such as Bidwell and Lynn.

"What can you expect their loyalty to be?" an NFLPA attorney said. "Are they supposed to be loyal to their own wallets, or to Billy Kilmer and Sonny Jurgensen's pension? That's easy."

The jury found that management failed to contribute $12.5 million between March 31, 1986, and March 30, 1987, and $5.3 million since then. In addition, the jury found management failed to make a $163,713 payment for interest owed from 1984.

The case went to court after the National Labor Relations Board ruled in 1987 that the NFL's actions were proper.