He says he has support for his call for the state to chip in $200 million dollars in bonds for the project.
Ricketts says business owners and union leaders like his plan.
All this comes after Governor Quinn and Mayor Daley said they are skeptical about the proposal.
The Cubs owner gave out some of the details of his plan during an interview with ABC 7 last week. However, Tuesday, he brought out his backup, a large group of supporters who say that they would like to see the Wrigley Field improvements for economic reasons.
The North Side ballpark that is home to the Cubs is a national landmark and a huge draw for tourists, bringing in tens of millions of dollars every year to the state.
But it is going on 100 years old. It needs work, and the Cubs' owners believe the state should help out by guaranteeing $200 million in bonds, to be repaid by a small portion of the entertainment tax on Cubs tickets.
"We have a proposal on the table that makes a tremendous amount of sense," said Ricketts. "It's a real no-brainer from the economic standpoint."
The Cubs owner was surrounded by union, business and political leaders who support the proposal. The main reason: economic development.
"This isn't about the Cubs, and it's not about the Sox, it's not about the North Side or South Side," said Jorge Ramirez, Chicago Federation of Labor. "It's about jobs. It's about 1,500 jobs for people. Some of whom have been out of work for one, two, or even three years."
"Any time you look at a project that is at the end of the day worth about $400 million, that equates to about $120 million that should go back into the minority community," said Larry Huggins, Riteway Construction.
The Cubs hope to use the money to update the ballpark, widening the concourses, upgrading the facility and improving training areas for players. They plan to do it during the off-season so the team could continue to play at Wrigley.
The Ricketts family also wants to build the so-called triangle building, which could include restaurants and a museum.
Most politicians support the development, but many are still debating the best way to pay for it.
"It is really a good plan, but we have to work some of the finances, because in a difficult economic time, which they are, that $4 million or $3 million-- that's a lot of money," said Mayor Richard Daley.
"This is not taxpayer money. This is the Ricketts family asking the state to do for the Cubs what they have done for all other kinds of other sports and tourism attractions," said Ald. Ricardo Munoz, 22nd Ward.
In the last decade or so, Ricketts said, The Tribune Company -- the team's former owner -- took a Band-Aid approach to keeping the ballpark open, fixing things as they came up. He said, if this proposal fails, he has no plan B, and the team would be forced to continue to try to patch things to keep the ballpark open rather than give it the makeover Ricketts said it deserves.