RULES GOVERNING DOUBLEHEADERS.
(a) (1) Only two championship games shall be played on one date. Completion of a suspended game shall not violate this rule.
(2) If two games are scheduled to be played for one admission on one date, the first game shall be the regularly scheduled game for that date.
(b) After the start of the first game of a doubleheader, that game shall be completed before the second game of the doubleheader shall begin.
(c) The second game of a doubleheader shall start twenty minutes after the first game is completed, unless a longer interval (not to exceed thirty minutes) is declared by the umpire-in-chief and announced to the opposing managers at the end of the first game. EXCEPTION: If the league president has approved a request of the home club for a longer interval between games for some special event, the umpire-in-chief shall declare such longer interval and announce it to the opposing managers. The umpire-in-chief of the first game shall be the timekeeper controlling the interval between games.
(d) The umpire shall start the second game of a doubleheader, if at all possible, and play shall continue as long as ground conditions, local time restrictions, or weather permit.
(e) When a regularly scheduled doubleheader is delayed in starting for any cause, any game that is started is the first game of the doubleheader.
(f) When a rescheduled game is part of a doubleheader the rescheduled game shall be the second game, and the first game shall be the regularly scheduled game for that date.
By rule a doubleheader must start twenty to thirty minutes after the first game is completed. Consequently, a "day-night doubleheader" is no doubleheader at all because it is two games scheduled at different intervals on the same day.
The umpire-in-chief is the sole timekeeper and judge of whether or not the second game is to start. Neither the home team manager nor management have jurisdiction in determining start time or whether the field is playable.