He also said that Tierney - a longtime marketing and communications executive - will remain as CEO of Brian Communications.
Tierney was an owner and head of the group that bought the Daily News and Inquirer for $515 million in 2006, as newspapers were on the cusp of an era of fast-shrinking readership and revenue, punctuated by the 2008 economic crisis.
The Tierney-led group ultimately filed for bankruptcy and lost the papers to hedge-fund investors in 2010.
In a statement yesterday, Tierney expressed sorrow over the death of Katz and condolences to the family, adding: "The Philadelphia Inquirer, Daily News and Philly.com play a fundamental role in our civic life. That's why Lewis and Gerry bought the papers last week. If during this transition period my expertise and qualifications can help the organization, I want to do so."
Despite the bitter bankruptcy fight, Tierney has kept his hand in the newspaper world. He is chairman of the Poynter Foundation, the fundraising arm of the Florida-based nonprofit institute for journalism, and he served briefly as a consultant to the Philadelphia newspapers last year, also in a bid to drum up ad dollars.
Also yesterday, Lenfest announced that Mark Frisby, a former publisher of the Daily News, will become associate publisher for operations.
He said George Loesch, senior vice president for sales and marketing, will continue until the closing of the sale, scheduled for this month, "but he has agreed to help as needed in the transition."
Last Tuesday, four days before the fatal jet crash, Lenfest and Katz had won an auction to purchase the news organizations for $88 million and end a contentious fight with former co-owner George Norcross. Now Katz's son, Drew Katz, 42, will be assuming his father's role.
The ownership team is seeking a full-time publisher, and a leader for Philly.com to replace Alessandra Norcross, George's daughter, who is expected to depart.
Also yesterday, it was announced that a memorial service for Katz will be held at 11 a.m. tomorrow at Temple University, where he was a trustee. The service will be at the Performing Arts Center, formerly the Baptist Temple, on Broad Street above Montgomery Avenue, North Philadelphia.
On Twitter: @Will_Bunch