The San Francisco 49ers may have slipped up here and there, but they still have one of the best defenses in the NFL. There's some really top notch defenses in the game today, but the top five probably includes the 49ers, and it probably includes their Week 2 opponents, the Seattle Seahawks. That game didn't go very well for the 49ers and their offense, which certainly hasn't been among the best in the league this season.
In Week 5, the 49ers will face the second-best defense they've faced this season: the Houston Texans. The biggest reason Houston is one of the top defenses is simple: they defend against the pass really, really well. Given that the 49ers only have two threatening receiving targets and one of them is a tight end, this could be a bad day for them.
That said, that pass defense is very good not just because there are good corners and safeties, it's good because the Texans have great players in their defensive front. Those guys harass the quarterback in any way they can and as it turns out, they have a lot of ways. Their job is going to be tough when they take on guys like Joe Staley, Mike Iupati and Alex Boone, but they will get through and they will force Colin Kaepernick to face that strong secondary.
The bigger problem: Kaepernick has not been good in these situations. This season we've seen poor decision-making, a lack of awareness of the football, said football's security and the players around him, abnormally long dropbacks in the pocket, the tendency to abandon the mid or even the deep ball, and any other way we can otherwise describe him as being pretty rotten in the pocket.
Keeping a clean pocket is the job of the offensive line, and I'd argue that they have done that an awful lot. Sure, some of Kaepernick's worst plays likely came in the face of pressure, but a large number came from him panicking early and abandoning a play. I'd go as far as to suggest that Kaepernick has demonstrated a pretty clear lack of faith in his offensive line, whether that be a subconscious or conscious decision.
At the end of the day, this game could wind up being a defensive struggle. San Francisco was great at defensive struggles in 2011 and 2012, but that hasn't been the case this year. Both teams have a very solid defense in both facets and both teams are hoping to take the other out of their comfort zone. Thus far, the 49ers have been easier to take out of that comfort zone.
That can't be the case this week.