This marks the first week that rankings counts for CIF team qualifying on a at-large basis.  See the following excerpt from the CIF-SS Season Preview:  

"AT-LARGE CRITERIA INTO DIVISIONAL PRELIMS - Any team not qualifying automatically from their league, who has been ranked in the top 13 in their division in 2 of the last 4 CIF-SS polls, will be invited to CIF-SS Prelims as an At-large team.  "

The four rankings that count for an at-large bid are 10/21, 10/28, 11/4, and 11/11.  

See the attached official rankings courtesy of Rich Gonzalez and PrepCalTrack.

CIF-SS Divisional Team Rankings - 10/21/2013