Posted by ESPN.com's Mike Sando
No NFC West defense ranks higher than Seattle's in yards per game or yards per pass play through Week 9.
The 49ers' defense has suffered in those areas after facing the Vikings, Texans, Falcons and Colts in addition to the Cardinals.
The Cardinals moved up to third in rushing yards allowed per game after the Bears made little effort to establish the run even before Arizona pulled away. The 49ers are fourth in that category despite having problems against the Titans' Chris Johnson. Seattle is 11th and St. Louis 27th.
Where NFC West defenses finished in yards allowed last season: San Francisco 13, Arizona 19, St. Louis 28, Seattle 30.