The Cleveland Indians game got rained out on Friday ... but there's still a lot to celebrate, 'cause Carlos Santana was officially sworn in as United States citizen!!
The Dominican slugger took his oath of citizenship in front of his family and friends in federal court in Cleveland earlier today ... after passing all the requirements to get dual citizenship.
Santana ain't the only Tribe player to earn his citizenship ... his teammate Hanley Ramirez -- who is also from the Dominican Republic -- was sworn in at a ceremony last week.
The best part?