What is the difference between a starter and a rotational player?

A starter is normally part of the lineup that begins the game, while a rotational player shares snaps according to personnel packages and game situations.

Rotational players can still have major roles. Defensive linemen rotate to stay fresh, receivers enter for different formations, and running backs may divide early-down, passing-down, or goal-line work. Snap counts and assignments often describe actual usage better than the starter label alone.