Owens is scheduled to report to the Ravens on Monday to take the physical. On Sunday, the receiver told WCAU-TV in Philadelphia that he would not report.
"I'm going to fight it [the trade] to the end until I can't fight it anymore," Owens told the station.
The statement came after several days of maneuvering. Gene Upshaw, executive director of the players' union, said Sunday that he had informed Harold Henderson, the league's executive vice president for labor relations, of his intention to try to get the trade overturned.
If the matter isn't resolved, the union will ask Stephen Burbank, who is in charge of settling collective bargaining agreement disputes, to have Owens' contract voided so he can be declared a free agent, Upshaw said.
NFL spokesman Greg Aiello confirmed that Henderson spoke to Upshaw about the case, but said there has been no resolution.
In the interim, the Ravens likely will have a chance to rescind the trade.
Since all players must pass a physical before trades are complete, the Ravens could choose to reject the trade if Owens does not take the exam, or they could waive that provision.
However, Ravens officials told the Baltimore Sun on Sunday that the team does not intend to void the trade if Owens does not take his physical.
"If we're comfortable enough after talking with [the 49ers'] doctors -- which I believe we are -- we can waive the physical," Ravens coach Brian Billick told the Sun. "But we have to wait for the league and the union to declare their position. Once they officially say, 'Look this is a trade and it's a done,' then the next step is for us is the physical by which we can waive right now. If he is of a mind that he won't come report for a physical, we can waive that and he's our property."
The players' association plans to file what is known as a "special-master case" in the next few days, Upshaw told The Washington Post for Sunday's editions.
A special-master case is a trial-like proceeding and differs from the usual grievance process, in which the parties present their cases to an arbitrator.
Burbank would then have the power to void Owens' current deal, allowing the receiver to negotiate with any team he chose, the newspaper reported.
"We think, at this point, that's the only case we can file," Upshaw said. "That's what we'll do the early part of next week. I want to talk to Harold Henderson in the early part of next week to see if there's something the parties can work out short of that proceeding. If not, that's what we'll do."
A league source told the Baltimore Sun for Monday's editions that the union has little chance of succeeding in its efforts, since it will concede that Owens' agent made a mistake by missing the paperwork deadline to make Owens a free agent.
The Ravens, if the trade is nullified, would have the second-round pick in the upcoming draft, which they sent to San Francisco for Owens, returned to them. At that point, Owens would also become an unrestricted free agent.
The Ravens said they expect Owens to wear their uniform this
"We made a trade that was OK'd by the NFL," Ravens spokesman
Chad Steele said Sunday. "We have a valid contract with Terrell
and we expect him to play for the Ravens this season."
Owens failed to become a free agent when he and his agent, David Joseph, missed a Feb. 21 deadline to exercise a clause in Owens' contract that would void the final three seasons of his deal.
Owens said in an interview with ESPN on Friday that he wants to
play for the Philadelphia Eagles, who are desperate for No. 1
He reiterated that desire to the Philadelphia station Sunday and said he expects to be an Eagle.
In that interview, Owens for the first time addressed the possibility that his bid for free agency and to join the Eagles may fail.
"I want to fight for my right to exercise the option in my contract," Owens said. "This is not to disrespect the Ravens organization by any means. I just want a fair shot at my free agency.
"If it comes down to the point where I can't win, I'll be a Raven. [But] I'm not going to Baltimore and act like I'm happy to be there when I'm not."
Owens' agent, David Joseph, did not immediately return a phone
call from The Associated Press on Sunday.
The Eagles reportedly agreed to a contract with Owens that included a signing bonus believed to be worth about $10 million and would have paid Owens more than $6 million a year. That deal was supposed to be a precursor to a trade that would have sent Owens from San Francisco to Philadelphia in exchange for a fifth-round draft pick and likely wide receiver James Thrash.
Before Philadelphia could complete a trade, Owens was traded to the Ravens for a second-round pick Thursday.
Under Owens' current contract, he is due to make $17.7 million in base salary over the next three seasons: $5.3 million next season, $5.9 million in 2005 and $6.5 million in 2006. The Ravens said Thursday they would try to negotiate a new deal with Owens, but those efforts have been impeded by the Eagles' proposal, according to the Post..
Upshaw refused to elaborate on the details of the union's case Sunday, but a source familiar with the proceedings told the Post that the union would concede that Joseph made a mistake by failing to file the paperwork in time to make Owens a free agent.
According to the Post's sources, the union intends to argue that Owens should be declared a free agent because it had been known his intention was to leave the 49ers.
League sources, however, have said the NFL considers Thursday's trade legal and a done deal, and sees no reason to overturn it.
According to the terms of the collective bargaining agreement, the special-master's decision is subject to review by U.S. District Judge David S. Doty, who over sees the CBA.
Owens caught 80 passes for 1,102 yards and nine touchdowns last
season -- his lowest totals since 1999. He has been selected to the
last four Pro Bowls but has feuded with teammates, coaches, the
49ers' front office and the media.
He has spent all eight of his NFL seasons with the 49ers, who
drafted him in the third round in 1996. He and Indianapolis' Marvin Harrison are the only receivers with more than 5,000 yards and 50
touchdowns over the past four seasons.
Owens is known for a series of on-field celebrations and
off-field conflicts. Two years ago, he pulled out a pen and signed
a ball after scoring a touchdown in Seattle. He wasn't fined for
the move but was chastised by commissioner Paul Tagliabue, who said
he would be disciplined for any future stunts.
Information from The Associated Press was used in this report.