Sportsbooks calculate odds by putting the amount that will need to be paid out to the amount of money that all bettors have paid. The sportsbooks try to keep both sides as even as possible.This is what it opened at and hasn’t moved.
They use terms like 'favorite_ and 'undrdog', but not it the context we generally use those terms.
Over the course of a week, a team could move from the favorite to the underdog with out anything else happening but an unequal distribution of bets.