Doubleheader

4 clues
D
Modern baseball rarity
Marathon at Camden Yards
Two games for the price of one
Similar answers:
Abnerdoubleday
Addledadoublelife
Adoubledactyl
Adoubleuoel
Agentroomheader
Atthedouble
Bodydouble
Bodydoubles
Bodydoublestandard
Checkanddoublecheck
Dailydouble
Dirtydoublecruiser
Doadoubletake
Dodoubleduty
Doesadoubletake
Doesdoubleduty
Dolleydouble
Double
Doublea
Doubleacrostics