Tribune Co. is preparing for a possible filing for bankruptcy-court protection as soon as this week, according to people familiar with the matter, in a sign of worsening trouble for the newspaper industry.

In recent days, as Chicago-based Tribune continued talks with lenders to restructure its debt, the newspaper-and-television concern hired investment bank Lazard Ltd. as its financial adviser and law firm Sidley Austin to advise the company on a possible trip through Chapter 11 bankruptcy, people familiar with the matter...