Today marks the 20th anniversary of the September 11 attacks ... and the man who caught President Bush's ceremonial pitch before World Series game 3 in NYC says #43 sent him a letter this week, commemorating the powerful moment.
TMZ Sports talked to former New York Yankees catcher Todd Greene -- who was Jorge Posada's backup at the time -- about that unforgettable October night in the Bronx, only 49 days after 9/11, when GWB fired a strike from the mound, symbolizing America's resolve.