Watch Now: Report: Yankees And Mets To Face Each Other On 20th Anniversary Of 9/11 (2:23)

To commemorate the 20th anniversary of the Sept. 11 terrorist attacks, Major League Baseball has scheduled a special all-New York matchup at Citi Field. The New York Mets will host the New York Yankees on Sept. 11, 2021. The matchup was part of MLB's 2021 schedule, which was released Thursday, and was first reported by Tim Healey of Newsday

The Yankees and Mets were part of the nationwide healing process following the attacks nearly two decades ago. On Sept. 21, 2001, the Mets hosted the Braves at Shea Stadium in the first pro sports event held in New York following the attacks. Manager Bobby Valentine and several Mets players visited Ground Zero and exchanged hats with first responders. 

Mike Piazza hit an emotional home run that night.

The Yankees advanced to the World Series in 2001 and President George W. Bush threw out the ceremonial first pitch at Yankee Stadium prior to Game 3. He wore a bulletproof vest and an FDNY jacket, and Secret Service personnel was stationed throughout the ballpark, including snipers on the roof of the upper deck.

Last year Mets slugger Pete Alonso gifted his teammates customized cleats with the American flag and the message: "We will never forget." MLB has not allowed either the Mets or the Yankees to wear first responder caps on the field since that Sept. 21 game at Shea Stadium. Maybe that rule will be relaxed next season. Also, Piazza throwing out the first pitch is a no-brainer.

The Yankees and Mets have never played on Sept. 11 and only once before have both clubs been at home in New York on that date. In 2014 the Mets hosted the Nationals at Citi Field while the Yankees hosted the Rays at Yankee Stadium.

The 60-game schedule for 2020 was released Monday.