by Rivers McCown

The year was 2013. The 49ers, after a tight opening-day win over the Packers, fell to 1-2 after getting stomped by Seattle and Indianapolis. A nation wanted to know what had gone wrong.

The answer is the same as it is now: San Francisco's indispensable weapon on offense is not Michael Crabtree, but Vernon Davis. Davis is the only receiver in the San Francisco passing game who is a sustained vertical threat for defenses. Anquan Boldin and Crabtree can get to the corner or the post, sure. But nobody in the receiving corps is the same kind of seam threat that Davis is.

Last year, Davis had a 72.1% DVOA on passes marked "deep" (over 15 yards past the line of scrimmage). San Francisco, as a whole, put up only a 32.2% DVOA on those passes.

But that only shows a tiny sliver of the impact that Davis has on the offense as a whole. Last season, Davis missed the Colts game and most of the Seahawks game, as well as most of the Carolina game because of a concussion. Here's how that turned out for San Francisco, the team that finished fourth in passing DVOA in 2013.

Table 1: Games Vernon Davis Was Limited In, 2013 Week Passing DVOA 2 -71.1% 3 1.0% 10 -68.5%

Those were the two worst games that San Francisco played last season as a passing offense, and three of the worst five. Yes, some of that is mashed in with the fact that Carolina and Seattle had amazing defenses. (They were first and third in defensive DVOA in 2013.) But if we can acknowledge that, surely we can acknowledge that the 49ers looked much better on offense against those teams in the playoffs with a healthy Davis.

In this game, without his vertical threat, the Cardinals clamped down on Colin Kaepernick. Kaepernick was able to complete 29 of his 35 throws, but for just 245 yards. That's 6.2 yards per pass. Arizona's stout defensive line, led by multi-gap clogger Calais Campbell, eliminated the running game from the equation. That meant Kaepernick had to play perfect football.

So, yeah, it's tempting to use that 1-2 start to figure out where Jim Harbaugh is going after the season, or talk about Kaepernick's non-franchiseness (the new "elite!") because he didn't overcome the circumstances.

Or, we could admit that Kaepernick is a really good quarterback who was playing against a really good defense without his most important weapon. And that there's a track record of this happening in the past. And that the 49ers will probably be just fine.

There, I made it through that entire section without inflaming anti-referee San Francisco tensions. Wait. Crap.

By the VOA

Team OFF DEF ST TOT ARI -1.6% 11.7% 4.5% -8.8% SF 12.4% 12.1% -9.1% -8.8%

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Yee-haw, we got ourselves a dead heat!

Phil Dawson missed a field goal for the 49ers. Pretty non-elite, if you ask me.

Somewhat related to that special teams discrepancy: The 49ers started from beyond their 20-yard line just once. The last three Cardinals drives started at the Arizona 34, Arizona 47, and Arizona 42.

Return of the Deep Ball

With Chuck Pagano indisposed due to leukemia, Bruce Arians took over as the head coach and signal-caller of the 2012 Indianapolis Colts. He took one look at the team and decided that, given the lack of running-game talent on the roster, he needed to double down on big plays.

And it worked, to an extent. There were a lot of incompletions as Andrew Luck grew into the job on the spot. Luck sported a 56 percent completion percentage to T.Y. Hilton, 55 percent to Reggie Wayne, 54 percent to Coby Fleener, and 46 percent to Donnie Avery. Dwayne Allen was the only regular Colts receiver to catch more than 60 percent of his passes that season.

But the Colts were able to score. They finished 18th in the NFL at 22.3 points per game, and just barely above-average at 2.3% DVOA. Luck threw the ball 662 times, more than all but three other quarterbacks.

The 2014 Cardinals are managing things in much the same way. Andre Ellington's foot injury may limit him all season, and with Jonathan Dwyer off the roster for domestic violence, the Cardinals are paper-thin in the backfield. It's to the point where they signed Marion Grice off the San Diego practice squad yesterday -- given how replaceable backs are viewed, it's a fairly rare move in the modern NFL. Add that on to the fact that Jonathan Cooper has not rebounded from injury as the Cardinals might have hoped, and the offensive line is also not getting much push in the run game.

Drew Stanton is not Andrew Luck. But he did have Andrew Luck's 2012 game plan on Sunday.

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Third-round draft pick John Brown is playing the small-school speedster role T.Y. Hilton had in 2012. Larry Fitzgerald is Wayne, the dependable old receiver who can still play. The 2012 Colts didn't have a Michael Floyd. Nor did they have a good defense. Thus, the 2014 Cardinals can hang with a team like the 49ers on any given week, if the deep shots go their way.

It's not terribly surprising that the Cardinals were able to exploit a pass defense without any star corners, especially when they get to pick on Jimmie Ward. Without Aldon Smith, the 49ers aren't getting much of a pass rush without bringing extra heat.

What is surprising is that Drew Stanton was able to wing it. As Chase Stuart pointed out on Twitter, Stanton's average pass depth Sunday went 13.4 yards. That's more than 3 yards longer than any other quarterback's passes last week. We haven't exactly been treated to a lot of Stanton film over the years, so it was impressive that he was able to flash the arm strength, if not the accuracy.

Perhaps if the 49ers employed some non-Davis receivers who could dominate on the upper part of the route tree like Arizona did, this loss wouldn't have happened.