Athletics

This is a "metameta puzzle" that uses the answers to the Baseball, Basketball, and Football metapuzzles, as well as all their feeder answers. You only need the first letter of each non-meta answer.

The first letters of the answers run from A-Z, without the letter J. This (and the flavor text) should give you an idea for what the 5x5 grid represents.

To construct the Playfair key, first you need to identify a set of "jersey numbers" for each team (between 1 and 25), then you need to solve a logic puzzle.

The answer to the basketball meta singles out a set of 5 numbers between 1 and 25 (and similarly for the baseball and football metas).

There are 5 square numbers and 9 prime numbers between 1-25 (and the 11 remaining "gaps" correspond to the football answers).

The top of the grid represents the keyphrase used in the construction of the Playfair cipher -- the unused letters that make up this key are AELMNPSUZ (keyphrase enumeration: 6 5). Use this Playfair grid to decode a certain 25-letter string.

Write down and decode the 25 initial letters of the puzzle names (in order of the Playfair grid/numbering).