Vikings got a glimpse of Kaepernick before he was famous

Before Colin Kaepernick was a Super Bowl quarterback, before he was the ESPY winner as "Best Breakthrough Athlete," before he suddenly drew 10-to-1 odds in Las Vegas to win the 2013 NFL MVP award, he was simply a 49ers backup working behind Alex Smith and fighting for second-team reps.

But maybe Kaepernick's emergence should have been more predictable. During the 2012 preseason opener, after all, he let loose against the Vikings for a quarter, providing a sneaky preview of the fireworks show that eventually helped San Francisco claim last season's NFC title.

In four series against the Vikings last August, Kaepernick ran for 92 yards and threw for 40. On his second snap that night, early in the second quarter, he lit a read-option mortar, taking a shotgun snap and faking a handoff to LaMichael James. With the entire Vikings defense washing right as if being pulled by a major undertow, Kaepernick darted into space.

Vikings safety Jamarca Sanford can still see all 78 yards of that play, from the San Francisco 22 all the way to the end zone.

"I remember it like yesterday," Sanford said. "I was part of that play trying to do too much. Bit inside on Cover 2, was trying to do too much, got a bad read and that was the end."

Chris Cook remembers that score as well. He was the last man with a chance to stop Kaepernick, shedding a block and giving chase. To no avail.

"It wasn't necessarily a helpless feeling," Cook said. "I was gaining ground. I just couldn't get there. As a defense, we played it too fast and gave up that backside. We weren't expecting it. But it won't happen again."

As the Vikings prepare for their reunion with Kaepernick tonight at Candlestick Park, there's an acknowledgment of just how valuable this preseason test might be.

"San Francisco is such a physical offense and they'll run that option," Sanford said. "So this is a great test for us of executing and playing smart and just doing your job without trying to do too much."

Gaining strength

To this point in the preseason, even with all the anxiety swirling around the offense's ineptitude, the Vikings defense has proved stingy. With the first unit intact last Friday in Buffalo, the starters played five series and allowed 69 net yards and no points.

Sanford provided an early takeaway, an interception off a Xavier Rhodes deflection. And that pick wound up in his arms only because he was a fraction of a second quicker to the ball than fellow safety Harrison Smith.

"Like Coach always say, you run to the ball and good things happen," Sanford said

In all, that defensive effort in Buffalo provided plenty to build on. The Bills sputtered to a trio of three-and-outs in their first five possessions. And their longest first-half drive stalled at the Vikings 21, resulting in a field goal.

Equally important, the defense held up against Buffalo's fast-paced, no-huddle attack.

"We were in a lot of situations — sudden-change situations, backed-up situations. And we executed pretty well," Cook said. "You can feel that trust within our defense, and the unity is there."

Final exam

Now comes the last big test before the regular season. Getting a full week to study the nuances of San Francisco's system should be beneficial, especially with so many other read-option quarterbacks on the regular-season docket. That list includes Cam Newton, Robert Griffin III, Russell Wilson and Michael Vick.

"It's a dry run-through for what the season is going to be like," Vikings defensive coordinator Alan Williams said. "I think the option game is here, for at least another year. … So it's good for us to test-run, test some ideas out, test some things out that we'd like to do and kind of see how they fare."

Williams made it clear to his players that while the NFL's hottest offensive fad must be studied and accounted for, there has to be balance within the preparation.

"When you actually count the number of times that [read-option] play comes up, it isn't as much as you'd like to think," Williams said. "But by the same token, if they run it four times, you don't want it to be four touchdowns or four big plays. … If you don't stop it, they'll run it again and again. So you do have to make sure you shut it down. But not at the expense of stopping a team's bread-and-butter plays."

Overall, the Vikings feel encouraged by their defensive progress and hope their final preseason dress rehearsal will provide another step forward.