The rotation for both the NFC West and AFC West changed. Reason for that was that prior to the change two teams would have shorter road trips, and two teams in the same division would have longer road trips.
In the AFCW the pairings used to be San Diego and Oakland (further) or Denver and Kansas City (shorter). That was changed to Oakland and Denver or San Diego and Kansas City; the result was that the Pats traveled to Oakland in 2011 as well as in 2008, while Kansas City came to Foxboro twice in a row.
Same situation with the NFCW. It used to be Seattle and San Francisco were paired together, and Arizona and St. Louis were paired together in the schedule rotation; now it's either Arizona and San Francisco or St. Louis and Seattle. Once again the change results in a one-time situation where we go to one team twice in a row (Seattle) and another team comes here twice in a row (Arizona).
After this year everything will be back on track as far the schedule rotation goes.