Since St. Mary's is essentially a D1 team, it stands that someone from D1 will be bumped down. Cosumnes Oaks and Inderkum are the most likely candidates.
The bottom five teams in D1 (that are eligible to move) from the smallest are Armijo, Cosumnes Oaks, Inderkum, River City, and Gregori.
Armijo and River City are highly unlikely to qualify for the playoffs. Cosumnes Oaks is a borderline team, so if they do not make the playoffs, Inderkum will be moved down and will be the presumptive favorite immediately.
If the winner of the Delta is also a D2 school (Elk Grove or Jesuit), then two teams would move down, coming from the smallest likely playoff teams: Cosumnes Oaks, Inderkum, and Gregori.
The next couple of weeks should really tell us something about Cosumnes Oaks' chances this season. They have Monterey Trail tomorrow and Sheldon next week. They don't necessarily have to win both those games, but two blow out losses would not bode well for their playoff chances.