MLB's Aroldis Chapman: I'm American, Baby ... Granted Citizenship

Aroldis Chapman now bleeds red, white and blue ... even though he kinda already did (see: Cuba's flag) ... because the Cuban-born pitcher is now a full-fledged U.S. citizen.

The NY Yankees fireballer -- nicknamed the "Cuban Missle" -- defected from Cuba (by way of the Netherlands) back in 2009 ... and has made it his mission to get full citizenship.

Well, Friday it finally happened ... and the 28-year-old proudly announced it on social media.

"Today is a very important day for me and I want to share it with all of you," Chapman wrote.