THE OWNER of the Chicago Cubs for the first time publicly threatened to move the team out of Wrigley Field if his plans for a big, new video screen are blocked, saying yesterday he needs new advertising revenue to help bankroll a $500 million renovation of the storied ballpark.

Cubs chairman Tom Ricketts until now had said nothing as dire, despite months of contentious negotiations over how to keep everyone happy in sprucing up the 99-year-old stadium in the heart of Wrigleyville on Chicago's North Side.

"The fact is that if we don't have the ability to generate revenue in our own outfield, we'll have to take a look at moving - no question," Ricketts told reporters after outlining renovation plans to Chicago business leaders.

He added that he remains committed to working out a deal and it is difficult to imagine the Cubs playing anywhere else. But the fight over the Friendly Confines boils down to money and, of course, something unusual - it's the Cubs, after all.

By far the thorniest issue is the plan for a 6,000-square-foot video screen over leftfield, a common feature in many major league ballparks. The difference is that Wrigley Field - the second oldest ballpark in Major League Baseball behind Fenway Park in Boston - is surrounded by privately owned clubs with rooftop bleachers whose owners object to any changes that could block their bird's-eye views into the stadium.

The rooftop businesses have been left out of discussions on the proposed upgrade, but they feel they should have a seat at the bargaining table because they have a contract in which they share 17 percent of their revenue with the Cubs. Legal action is a possibility.

Ricketts presented an architectural rendering of the video screen during his speech to the City Club of Chicago and insisted that the team's own studies have shown it would have minimal, if any, impact on the views. He described the sign as "midsize" compared with those at other stadiums, thought it is nearly three times as large as the scoreboard currently atop the centerfield bleachers. Another smaller sign with the name of a sponsor is planned for rightfield.