Several bidders offering between $700 million and $900 million for all the properties have been excluded from the second round, according to the person, who spoke on condition of anonymity because of nondisclosure agreements governing all talk about the bids.
A Tribune spokeswoman said the baseball team would not have any comment on the status of the sale, which also includes the team's minority stake in a Chicago regional sports TV network.
Included in the second round are Internet billionaire and Dallas Mavericks owner Mark Cuban; the Ricketts family, which founded the brokerage that is now TD Ameritrade Holding Corp.; and a group led by Sports Acquisition Holding Corp. that includes former baseball home run king Henry Aaron and former Republican Congressman Jack Kemp. The last group is believed to be teaming with another bidder who submitted an offer in the initial round.
All three of the reported potential buyers refused Thursday to comment publicly. However, the person involved in the bidding provided to The Associated Press an outline of the conditions for the second round.
John Canning, the chairman of private equity firm Madison Dearborn Partners LLC, which had been treated as the front-runner, did not make the initial cut, according to the person, who said Tribune is not letting any bidder eliminated after the first round submit a new higher proposal in the second round.
Canning is a minority owner of the Milwaukee Brewers and close friends with Major League Baseball Commissioner Bud Selig. Any successful sale must be approved by three-quarters of the owners of other major league teams.
Canning did not return calls seeking comment.
The bidders still in the running will get more detailed financial information on the Cubs, Wrigley and the sports network before they are required to submit a new proposal.
A person familiar with the Ricketts family bid confirmed that it is one of those invited back.
The Cubs lovable losers who haven't won a World Series in 100 years are expected to fetch more than the record $660 million paid for the Boston Red Sox, their ballpark and 80 percent of their TV network in 2002 by a group headed by Florida commodities trader John Henry.
Tribune paid $20.5 million for the team in 1981. It is now seeking to sell the team and its stadium to help pay off the $8.2 billion cost of going private last year.
The value of Wrigley Field apparently has been harder to quantify, since it may require hundreds of millions of dollars in renovations.
The state-run Illinois Sports Facilities Authority offered about $400 million to buy Wrigley using taxable bonds that would be repaid with lease revenue. Those talks broke down in May over how the ISFA would finance renovations and improvements at Wrigley, the second-oldest ballpark in the country behind Boston's Fenway Park.
Former Gov. Jim Thompson, who is chairman of ISFA, said his agency estimated the cost of improving the stadium structure and the player and fan amenities between $400 million and $600 million.
Tribune has said it is willing to sell the properties individually.