A new channel devoted to the Cubs is one of the enticing potential revenue-generating items that Tribune Co. is floating as part of its planned sale of the Chicago Cubs, Wrigley Field and its 25 percent stake in Comcast SportsNet.

So far, the media company has provided few financial details about Comcast SportsNet in the confidential briefing books it provided to prospective buyers, making it difficult to calculate a price tag for the channel, according to sources familiar with the documents, who asked not to be identified because the sales process is ongoing. Opening bids for the team are due by Friday.

But Tribune Co. also planted a seed of opportunity with prospective buyers. After Comcast SportsNet's rights to broadcast Cub games expires in 2019, a new owner could create a new sports network dedicated to the Cubs.

The idea is a tempting prospect, considering the size of the Chicago media market, the popularity of the Cubs and the success of other regional sports networks in large markets. On Comcast SportsNet, the Cubs draw more viewers by a wide margin than the other three pro sports teams shown on the network: the White Sox, Bulls and Blackhawks. The network, created in 2004, is jointly owned by the owners of the teams and Comcast Corp., the Philadelphia-based cable giant.

But future media opportunities for a new Cubs owner may have their limits. About 70 of the 162 Cubs games are also shown on Tribune Co.-owned WGN-Ch. 9. It's unclear whether Tribune Co., which also owns the Chicago Tribune, would obligate the new team owner to continue broadcasting games on the local station, which has a 60-year history with the Cubs. A Cubs-only cable channel also would lack the winter programming now provided by the Bulls and Blackhawks. And if Comcast is not a partner in a future network, a new owner would have to negotiate distribution rights.

"One of the qualifying factors is you've got WGN owned by the Tribune," said Andrew Zimbalist, a Smith College economist who focuses on sports. "As long as that's going on, the potential for a Cub-affiliated regional sports network won't be reached. That's not to say it won't be extremely profitable."

New source of wealth
Team ownership of regional sports networks has increasingly become a new source of wealth for professional sports franchises. Teams like having control of their broadcasts, as well as the revenue streams from advertising and subscription fees charged to cable operators. The subscription fees have been rising steadily in recent years because the channels are must-haves for cable and satellite operators that don't want to upset rabid sports fans.

The model of success has been the New York Yankees' YES Network. Its revenues, which include other sports programming besides the Yankees, exceed $300 million, and its cash flow, a critical measure of the network's health, was about $186 million in 2006, according to The New York Times. YES' value has been estimated at $3 billion, more than two times the $1.3 billion valuation that Forbes magazine placed on the Yankees.

In Major League Baseball, about a dozen teams have developed their own networks to air their games, said Lee Berke, president of LHB Inc., a sports-television consultant. Among the four major sports leagues, Berke estimates that about a quarter of all teams have ownership interest in a regional sports network.

Not all successful
But such a channel does not work in all markets. The Minnesota Twins baseball team abandoned its efforts in 2004 after it couldn't reach deals with cable systems and satellite services.

Thanks to its on-field success, the Cubs are averaging a 4.9 rating (about 170,000 households) on Comcast SportsNet at the All-Star break, an increase of 53 percent from the same time last season, the network said. Viewership of the White Sox also is up, but not as much. The South Side team is averaging a 1.9 rating, up 27 percent compared with last season's 1.5 rating at the midseason point.

The ratings boost has allowed the network to increase its advertising rates since the beginning of the year, said Jim Corno, president of the cable channel. He declined to comment on the planned Cubs sale.

Comcast SportsNet does not disclose its revenues to the public. A report by SNL Kagan last year estimated the Chicago network's 2006 revenues at $137.8 million. The report was published by trade magazine Multichannel News. About 80 percent of the channel's revenues came from subscriber fees. It charged a blended rate of $1.90 per subscriber per month, according to Multichannel News. By comparison, YES charged the most, at $2.15.

If Comcast SportsNet sells at 15 to 20 times cash flow, it would be valued at $827 million to $1.1 billion, according to Multichannel News, which used 2006 revenue data provided by SNL Kagan.

"[Comcast SportsNet] is a valuable asset," Berke said. "Any new owner is going to think twice about jeopardizing that value when looking at other media opportunities in future."