Supermarket magnate Ron Burkle will join with a union representing 2,000 workers at

Dow Jones

( DJ) to explore a bid for the publisher that can compete with Rupert Murdoch's $5 billion offer.

Tim Martell, a representative with the Independent Association of Publishers' Employees, confirmed Tuesday that Burkle is joining forces with the union, which has voiced strong opposition to a sale of

The Wall Street Journal

publisher to Murdoch's media conglomerate,

News Corp.

(NWS) - Get Report

.

Shares of Dow Jones reversed early declines on the news during Tuesday's trading session to climb 88 cents, or 1.5%, to $61.04. That's above the $60-a-share buyout price that Murdoch has proposed, signaling that investors believe a higher offer may be coming.

The news of Burkle's alliance with the union, first reported by the

Journal

, comes after a meeting between Murdoch and members of the Bancroft family, Dow Jones' controlling shareholders, on Monday. Murdoch is seeking to assuage concerns about his dedication to the company's tradition of editorial independence.

Murdoch reportedly said late Monday that his four-hour meeting with the Bancroft family in New York City was "constructive," but the two sides have yet to reach an agreement on safeguards for the publisher's editorial standards. Despite those differences, the direct talks mark a victory for Murdoch in his quest to own Dow Jones, since the Bancrofts initially declined to consider a deal.

The resistance on the part of the Bancrofts stems in large part to News Corp.'s record as a media operator that allows its business and political interests to influence its editorial process at media properties like Fox News and the

New York Post

. Similar concerns have been voiced by Dow Jones employees.

The depth of Burkle's interest in Dow Jones is unclear. A spokesman at his firm, Yucaipa Cos., declined to comment.

Burkle enters the fray at Dow Jones having suffered a series of defeats in his own efforts to buy a high-profile newspaper publisher. He joined with unions in a failed attempt to buy Knight-Ridder before it was sold last year to

McClatchy

(MNI) - Get Report

, and he also launched a failed bid with philanthropist Eli Broad to acquire

Tribune

( TRB) when it was up for sale.

No formal bid for Dow Jones to rival News Corp.'s offer has emerged, though the publisher has signaled it will entertain competing proposals. On Monday, the IAPE said in a statement that it was reaching out to a number of "substantial investors" in an effort to find another potential owner.

"IAPE believes that the best safeguard to the independence and integrity of Dow Jones would be the continued stewardship of the Bancroft family, but if the family is persuaded that a sale of Dow Jones is necessary, IAPE believes that there are alternatives to

Rupert Murdoch," the union said in a statement. "We are hopeful that the Bancroft family, with its long-standing commitment to the integrity of Dow Jones, will consider these alternatives."