[Owlkev71]

Why do the pitchers need so much rest?

Teams generally have 5 starting pitchers who do the bulk of the work, the teams play a 162 game schedule with about 15-20 off days, teams generally play at least 6 times a week, that's why they have the rest.

A starting pitcher will throw roughly 225 innings these days which equates to 30 games per starting pitcher.

It was different when Baseball began in the late 1800's, some pitchers threw 600 innings and played 60-70 games.