Ballpark quartet Crossword Clue

 The answer to the ballpark quartet crossword clue is BASES.

The bases are the four points on the baseball field that a player must touch in order to score a run. They are located at first, second, third, and home plate.

The bases are often referred to as a quartet because they are four in number and they are located in a square formation around home plate.

The crossword clue is a reference to the fact that the bases are a key part of the game of baseball. They are the points that players must touch in order to score runs, and they are also the points that runners must avoid being tagged out on.

I hope this helps!