Brock Purdy vs. Vikings review: The 49ers QB plays surprisingly well

If you’ve been reading this site for the past couple of years, then you know the statistic that I reference the most and believe paints the best picture is success rate.

Kyle Shanahan’s offense is predicated on staying on or ahead of schedule. All he needs is a quarterback to properly diagnose what the defense is doing and play on time. Brock Purdy has proven to be that player.

Two fourth quarter interceptions by Purdy took the place of what was an otherwise typical, efficient performance by Brock. Purdy’s success rate was 18 percentage points higher than Vikings quarterback Kirk Cousins on Monday night, and 41 percent of his passes resulted in a first down.

Combing through the box score makes you wonder how the 49ers didn’t reach 30 points. The Vikings had the ball for nearly ten more minutes than the 49ers, and ran 13 more plays. But the Niners had 19 first downs on 53 plays, averaging north of six yards per play.

But when you only have nine drives, and turn it over three times in the opponents’ territory and miss a field goal on another, we have our answer as to why the scoreboard said 17 after the game.

Week 7 was only the second time this season where Purdy attempted at least 30 passes. It’s in Kyle Shanahan’s nature to run the ball, use play-action, and put his quarterback in the most ideal situation.

But when you’re without your left tackle to run the ball or don’t have as many possessions as usual because your defense can’t get off the field, you’re left with no option but to put the ball in the hands of your quarterback.

The Vikings defense didn’t give Shanahan much of a choice, as running back Christian McCaffrey saw an 8-man front on 46 percent of his carries. Minnesota’s plan was to load the box and force the 49ers to throw.

This isn’t a training wheels offense that Purdy is running — far from it, actually. Shanahan only used play action on three of Purdy’s 33 dropbacks.

On the season, the 49ers are using play-action at the fifth-lowest rate. The majority of their offense revolves around a quick passing game (57%), where they lead the league in success rate.

Purdy’s timing is a big reason why the 49ers lean so heavily on the quick game. This throw to Brandon Aiyuk is a perfect example:

The ball is coming out before Aiyuk gets out of his break, and he doesn’t have to break stride or each back to catch the ball.

Purdy didn’t struggle against the blitz. He got the ball out before the rush could get to him, and found the open receivers for first downs.

Purdy finished the night being blitzed on 21 of his 33 dropbacks, which was expected from a Brian Flores defense. Purdy ended up 15-for-19 for 102 yards, a touchdown, an interception, and ten completions for first downs. He also had a couple of scrambles where he kept the play alive, and even ran for a first down.

Here’s a look at Purdy’s passing chart from Monday night:

Thirteen completions at or above ten yards should serve as music to Shanahan’s ears. Of course, you can’t overlook the red, but where the green occurs should restore any confidence lost in Purdy.

I came away from Monday night’s game thinking Purdy is still the “guy” to help the 49ers reach and win a Super Bowl. Fourth quarter turnovers can’t happen, in any circumstance, and Purdy knows that. But I also thought only one of the interceptions was his fault.

The 49ers had an 11 percent positive net success rate against the Vikings. Minnesota dominated on the variance plays, which is why they were victorious.

Purdy is in the concussion protocol, and the Niners may be forced to turn to their enigmatic backup against the Bengals. Shanahan is holding out hope that Purdy can still play:

“No, I mean, Brock didn’t take a practice versus Seattle in Thursday Night football until pre-game warmups, and he had to shut those down a little bit too. So he didn’t really get a real rep that week until play one, and he played pretty good. So, we’ll probably stick with that.”

Purdy also didn’t have concussion symptoms a few days prior, nor was he in the protocol.

50 shades of Sam

Recent history is against Purdy’s chances of being cleared the same week after being placed in the concussion protocol. For every one example of a player cleared, you’ll have to scroll another five or six to find the next.

Sam Darnold feels like he’s been in the NFL for a decade, but he’s only 26. Despite playing in the league and starting for a significantly longer period than Purdy, there are areas Darnold can learn from in this offense where Purdy took advantage of.

The safety at the bottom of the screen bails out late. Purdy recognizes it, and it appears that he gives Aiyuk a signal pre-snap, and the 49ers pick up a first down on 2nd & 8. Those are the types of plays that we take for granted.

When a team like the Vikings puts eight defenders in the box, taking those quick types of passes are ways to steal yards, first downs, and possessions.

Jimmy Garoppolo and Purdy have shown that a competent quarterback can flourish in Shanahan’s scheme. Purdy has elevated the offense thanks to his quick processing and ability to make the defense defend the entire field.

Another attribute that Purdy brings to the table that Garoppolo didn’t is his mobility. There were four or five plays from the Vikings game where Purdy ran out of a sack and turned a negative into a positive.

Darnold has mobility and superb athleticism which allows him to change directions and maneuver in and out of the pocket while avoiding taking a sack. However, Darnold can learn from Purdy when it comes to scrambling.

Purdy looks to get the ball out of his hands quickly in the face of pressure. He’s thinking the double, and if it’s not there, Brock takes the single. Either way, he’s always taking a profit.

Darnold is more like the hitter in the batter’s box who swings for the fences every time. It’s a big reason why Darnold has always been a high-variance quarterback.

Sometimes, he’ll throw a beautifully layers pass over the defense for an explosive play. Other times, Darnold launches it into triple coverage because he has the arm talent to even think about attempting that throw.

Darnold should mimic Purdy’s approach when he’s under center: Take a profit.