Pitching rotation

From BR Bullpen

The pitching rotation is comprised of the starting pitchers (usually 5) that a team plans to use over the course of the season. The pitchers in the rotation have higher stamina than relievers and, generally speaking, a wider variety of pitches. They are expected to pitch every 5th game. The rotation is set in a descending order of the pitchers' effectiveness. The top 1 or 2 spots of the rotation are generally given to the most talented pitchers-- the "aces" of the staff. The 5th pitcher of the rotation may be skipped over occasionally, especially in the first half of the MLB season, when there are more days between games that allow for the pitchers at the top of the rotation to get more rest. Some teams even forego the 5th pitcher altogether, using a 4-man rotation in tandem with occasional starts from a long reliever.