The move came after Big Trial, a website sponsored by the Beasley law firm, reported that leaders of the Newspaper Guild, the union representing journalists and many other IGM workers, were worried that one of the dueling owners' factions might be considering rehiring Tierney as publisher and CEO.
It also came as the union said it was trying to lead a group to buy out "either or both" of the factions fighting to control IGM, which operates The Inquirer, the Philadelphia Daily News, and Philly.com.
Bill Ross, executive director of the Guild, said the decision to end Tierney's contract "would probably be the smartest business decision this ownership group has made."
As publisher and CEO from 2006 to 2010, Tierney earned the ire of union leaders for job cuts and wage concessions. He lost control of the newspaper company when it was forced into bankruptcy. Since he left, Tierney has established two companies, Brian Communications and Real Time Media, a digital ad firm.
Rumors of his return as publisher were discussed during separate meetings held two weeks ago between Guild leaders and the main feuding partners, Lewis Katz and George E. Norcross III.
Norcross said Tierney would only regain the job "over my dead body," according to two people present.
On Tuesday, the union disclosed for the first time that it had tried to "play peacemaker" by assembling a group to buy out one or both sides.
"We have been repeatedly rebuffed," its leaders said in a message to members, who also include advertising, finance and circulation workers. If the partners cannot settle their differences, the union said, "we urge them to step back and allow an impartial industry expert to run the operation - or walk away."
Ross declined to name any potential investors the union had talked to. He said he and union president Howard Gensler, a Daily News columnist, were scheduled to meet with IGM chairman H.F. "Gerry" Lenfest on Wednesday about possible settlement options.
A spokesman for Norcross and three other owners allied with him hailed the Guild's statement. "The majority owners, who together own 58 percent of the company and represent four of six directors, applaud the Guild's statement this evening and stand ready to work with them to resolve these issues," they said in a statement. "The majority owners neither wanted, nor began this litigation."
Norcross and Katz are awaiting a decision from a Philadelphia judge on whether their dispute will be litigated in the city or in Delaware, where IGM was incorporated.
Their differences spilled into the open Oct. 7 when publisher Robert J. Hall fired Inquirer editor William K. Marimow. Katz and Lenfest, who also is a co-owner, sued to reverse the firing and remove Hall. Norcross countersued in Delaware Chancery Court, arguing that the case belongs there because the company was incorporated in Delaware last year.