The news came as two sources with knowledge of the matter told Reuters that the Italian club's Chinese majority shareholder had failed to meet a deadline on Friday for a 32 million euro (A$50.16 million) payment due to the team.
"The entire family and the family's financial resources are involved in this matter," the Ricketts said.
"The Ricketts family brought a championship to the Chicago Cubs through long-term investment and being great stewards of the team ... They would bring this same approach to AC Milan," they added.
Former Italy Prime Minister Silvio Berlusconi sold the Serie A team last year to businessman Li Yonghong, who has been making capital injections into the club under the terms of the agreement.
On Friday, he failed to honour the final 32 million euro payment due as part of an overall 120 million euros (A$188.11 million) owed to AC Milan, the sources said.
That is likely to prompt U.S. investment fund Elliott, which helped finance Li's acquisition of the club, to fill the capital shortage. If Li cannot repay Elliott by the end of the month, the fund manager could gain full ownership, the sources said.
Seven times European champions AC Milan are trying to emerge from years of financial losses with a turnaround plan.
Li has been looking for months for new investors to share the financial burden of the club, who spent 230 million euros (A$360.55 million) on players in the latest transfer window.
Li is being advised by investment bank Alantra in the search, two sources said.
The Ricketts family are working with Morgan Stanley, a source familiar with the matter said.
The Ricketts purchased the Chicago Cubs in 2009 and brought the team their first championship in more than 100 years after investing to bring in new players and managers, renovate the stadium and expand the club's business operations.
AC Milan are expected to close the financial year to end-June with a loss of 75 million euros (A$117.57 million), a source close to the matter told Reuters last week.
They are also facing possible sanctions for breaching financial fair-play rules after the club failed to reach a settlement agreement with European football's governing body UEFA.