Possible Clues:

• Buc or Met
• Nat or Card
• Cub or Dodger, briefly
• Player in baseball's 'Senior Circuit'
• Cubbie, e.g.
• SF Giant, for one
• Pitcher who bats, e.g.
• Member of the Brew Crew, e.g.
• D'back or Card
• NY Met, e.g