By Megan Davies and Ben Klayman

It was unclear which of the three bidders has been selected. However, the source said groups led by Tom Ricketts, chief executive of Chicago investment bank Incapital LLC and the son of the founder of TD Ameritrade Holding Corp; and Marc Utay, a managing partner with New York-based private equity firm Clarion Capital Partners LLC, have moved ahead of Chicago real estate executive Hersh Klaff.

Tribune Co, which owns the Cubs, has wrestled with the differences in the bids submitted by Ricketts and Utay, whose group includes private equity chief Leo Hindery, three sources familiar with the process said. Ricketts' bid includes more cash up front, while Utay's offers a higher overall value.

One source said Ricketts appeared to be the favored bidder, but that could not be confirmed.

Tribune filed for Chapter 11 bankruptcy protection last month due to its heavy debt load and the weak U.S. publishing sector. It put the Cubs on the block in April 2007, when Tribune agreed to an $8.2 billion buyout led by real estate magnate Sam Zell.

Bidders are anxious to take control of the team, which has not won a World Series title since 1908 but is nationally recognized due to its history as lovable losers and its national exposure on cable TV.

While the Cubs are not part of the bankruptcy, creditors must sign off on the deal because they will receive any proceeds, which analysts have said could approach $1 billion.

Tribune officials and a spokesman for the attorneys representing the creditors, as well as Utay and Ricketts declined to comment. Klaff could not be reached.

One proposal has been submitted to the Tribune's unsecured creditors' committee, said the first source, who asked not to be identified because the process is ongoing.

The creditors committee has a regularly scheduled meeting set for Thursday and the Cubs are due to be discussed, said another source involved in the discussions.

Approval from the creditors is expected by the end of the week and the aim is for Tribune to be negotiating with just one party by Monday, the first source said. However, the other two groups could still increase their bids.

Tribune has not submitted a winning bidder for approval by Major League Baseball, said a fourth source familiar with the process who asked not to be identified. An MLB spokesman referred questions to Tribune.

Any winning bidder will need 75 percent of the 30 team owners to approve the deal and that process can take up to two months as baseball officials investigate the potential new owner and the financial structure of the offer.

Tribune aims to negotiate final terms with a winning bidder before early February and possibly have a new owner in place by opening day in early April, Cubs Chairman Crane Kenney previously said. However, several involved in the process and bankruptcy court experts questioned whether the process can move that fast.

The Cubs open their season April 6 in Houston, and their first home game in Wrigley Field, also a part of the sale along with a stake in a sports cable TV network, is April 13.

(Additional reporting by Robert MacMillan in New York)