Notes: This list is intended as a fun starting point to see whose career paths intersected with John Costello's. It's not meant to serve as a comprehensive list, since teammates without a BaseballLibrary.com page are omitted. Also, since our data doesn't cover exactly when certain players were called up or traded during a given season, there may be some players here who played on the same team as John Costello during a season but never actually played with him.