Mets fans, some of whom likely have yet to fully dry their eyes after a heartbreaking loss in the seventh game of the National League Championship Series, will get to celebrate on Monday, at a ceremonial groundbreaking for their new 45,000-seat ballpark.

In April, the Mets announced details of plans to build an $800 million stadium in a parking lot adjacent to their current home in Flushing. Preliminary construction has already begun, and the Mets hope to complete it in time for the 2009 season, the same time the Yankees are scheduled to begin playing in a new stadium.

The Yankees broke ground on their new $1 billion stadium in the Bronx with an elaborate ceremony in August.

The new Mets ballpark will contain 12,000 fewer seats than Shea Stadium and will carry a different moniker, most likely the name of a corporate sponsor. The stadium design, by the firm HOK Sport, is expected to evoke Ebbets Field, the home of the Brooklyn Dodgers before they were moved to Los Angeles in the 1950s.

The city’s support for a new Mets ballpark was announced in June 2005, just days after Mayor Bloomberg’s plan for a football and Olympic stadium on the West Side of Manhattan was rejected. Originally, the new Mets stadium also was to serve as an Olympic stadium, but New York City failed to win its bid for the 2012 Olympics.

The city is planning to contribute about $90 million and the state about $75 million toward infrastructure improvements. In May, the City Council gave final approval for the city to issue $632 million in tax-exempt and taxable bonds, which the team will pay back over time.