49ers' opponents stacked against the run

So why is 49ers running back Frank Gore back to facing defenses with eight players crowded near the line of scrimmage? Entering Week 3, Gore has 60 yards on 30 carries, his lowest two-game rushing total in contests he's finished since his rookie season in 2005, when Kevan Barlow was the starter.

http://www.sfgate.com/49ers/article/49ers-opponents-stacked-against-the-run-4826535.php