In a perfect universe, or at least a perfect 2018 universe, or at least a manager’s perfect 2018 universe, a baseball team would have five starting pitchers, who would all stay healthy. A team that has played 110 games, such as the Giants, would feature five starting pitchers who had all pitched 22 times (give or take as they reshuffle the rotation around breaks).
That is not the Giants. That is not anything resembling the Giants. The Giants have used nine starting pitchers. One wasn’t supposed to make the Majors this year, or perhaps ever; he leads the rotation in ERA and FIP.