BOSTON — Behind just about every major league baseball player from the Dominican Republic is a game called vitilla. It is the country’s version of stickball, and it is played with a broomstick for a bat and the cap of a large water jug for the ball. And that cap can move more wildly than a Wiffle ball.

So as the 2017 postseason moves into full gear, with eight teams playing in the first round and Dominican position players and pitchers almost certain to make an impact in numerous games, vitilla (pronounced vee-TEE-ya) should probably be listed in the credits.

“It was the easiest game to play since everyone had the bottle caps, and we always played in the neighborhood after school,” said Starlin Castro, the Yankees’ second baseman.