The current MLB schedule allocates a total of 25 off days, setting the 162-game season into a 187-day calendar. Four of those days go to the All Star break, and one comes the day after Opening Day, and on average, another day is sucked up by a make-up game towards the end of the season.
The nature of the MLB calendar has led to a number of growing trends — managers’ reluctance to use relievers three days in a row, and the higher number of pitchers per game has necessitated larger rosters. Anyone who’s watched a Yankee game over the past three years has seen them adopt an informal scheduled rest system, giving players an extra day off in July so they’re hopefully fresher come October.