The Lineup Protection feature provides lineup insurance. This optional feature handles the case where a player in your starting lineup is marked "Out" or on "IL" but still occupies a starting slot on your roster.
With Lineup Insurance active, a player from your bench who is eligible and available for that slot will be selected and replaced for you.
NOTE: This only replaces players who are "Out" or "IL" with available, eligible players on your bench. It is NOT a lineup optimizer!