Select "Homerun Race" mode, then choose "Single Play". Then at the team selection screen on controller two, press X, Circle, Triangle, Square. Now the Oldboys will become selectable.
At the uniform selection screen on controller two, press X, Circle, Triangle, Square. Now the Oldboys will become selectable.
Select "Homerun Race" mode, then at the stadium selection screen on controller two, press X, Circle, Triangle, Square.
Select "Homerun Race" mode, then at the stadium selection screen on controller two, press Square, Triangle, Circle, X.