While the NFL is expanding the regular season by one game (and one week), it is consequently also shortening the preseason by one game, as contractually obligated, since the CBA states that any season in which there are 17 regular season games cannot contain more than three preseason games.
It does not, however, shorten the preseason calendar, nor keep the total playing calendar the same length. That’s because instead of a fourth preseason game being played, teams will simply have a week off, like a bye week, prior to the start of the regular season, according to Pittsburgh Steelers president Art Rooney II.