Sleeper Cell

What changes with Brock Purdy under center for the 49ers? Efficiency.

by Rivers McCown
Updated On: December 6, 2022, 12:51 pm ET

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The 49ers scored 33 points despite starting Brock Purdy at quarterback for the majority of their win over the Dolphins. It's an undisputable fact. What's also a fact after actually watching what happened in that game is that getting Purdy to deliver NFL-level passing offense sets up to be Kyle Shanahan's greatest test yet. I'm not entirely unconvinced that the 49ers won't eventually swap to Josh Johnson, but let's have a look at what actually happened. 

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Of Purdy's throws downfield that were completed, there was maybe one accurate throw into a zone. Most of them were balls where the receiver was either schemed wide open or Purdy floated away from the play for long enough to deliver an out-of-structure ball to someone that didn't need to have mustard on it. 

Purdy finished the week with an average intended air yards per attempt of 5.3. That would be the lowest of the season if Purdy had enough attempts to qualify -- Matt Ryan has a 6.2 figure on the season. It's not quite the most regressive pass offense of the season because what the Panthers did when Steve Wilks first took over was pretend that throwing the ball was a war crime, but it was a rough watch. Jimmy Garoppolo has done 6.7 intended air yards per attempt this year, and while that's not a number that fills you with optimism, he also hits more of the open passes than he misses. Purdy cannot claim that yet. 

Here the Dolphins jump the tight end on the over route, leaving Deebo Samuel wide open on the post. All Brock Purdy has to do is float this to a spot where Samuel can catch it. He can't do it. Perfect protection in the pocket. Perfect play call. Samuel has a step to the inside. He has to stop and come back to it, and the ball is broken up.

Purdy ended the first half with just over 110 passing yards, 74 of which came on the two-minute drive when Shanahan got to work scheming things up. 

I thought Purdy came back looking much more comfortable in the second half, but he also displayed some Case Keenumitis -- by which I mean he reminded me of young Keenum with this sack where he was running backwards:

You see, one thing that you can't do when you're not Justin Fields or someone like that is run backwards. You can't do it! Not against NFL athletes. 

None of this is altogether unsurprising because Purdy was not the most impressive college prospect. He was one draft pick from being undrafted. He did have a remarkably good preseason run with an 83.6 PFF pass grade on 99 dropbacks -- 346 yards on 49 attempts, one touchdown, one interception, and four sacks taken. But his long completion was 30 yards. His velocity was a problem at Iowa State. I think he has enough confidence to take tight-window throws, but much like Ryan, I don't know if his arm can cash that check consistently.

I jump on his lack of skill but I think it says a lot about the 49ers that they won this game despite their quarterback. I think the ultimate hope is that, kind of like Cooper Rush, the 49ers can box him in to a game plan that always makes him work and the defense makes sure they don't need to ask him to do anything more. That's not much different than Garoppolo! But the difference is in the consistency. 

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The aftereffects

I think the 49ers may find it slightly harder to run the ball for the rest of the season because teams are going to live with Brock Purdy trying to beat them because he's, well, Brock Purdy. I don't say this because I think he has no prayer at developing into something better than he looked in his first game, but because picking on the lowest rung of the totem pole is how the NFL generally works. Purdy just didn't look good. 

But fantasy-wise, I think this will remain a great situation for Christian McCaffrey and Deebo Samuel because it will literally all be on Shanahan to get these guys the ball. I think Purdy maintains some scant QB2 superflex value on the back of the offensive structure and the players around him. The whole point of Shanahan's offense is to get athletes like these two in to space and let them work. Or sometimes, as we saw on Sunday, to just let them work without space: 

I think we get caught up sometimes in regression and expected fantasy points and as an industry it's easy to just make these guys inputs and outputs. Samuel is a 1/1 player. He defies regression because he defies everything. Nobody should be able to do the things he does on a football field. He does them anyway.

My takeaway as a whole is that the 49ers pass efficiency will become more hit-or-miss. I think in the games where they can run, they'll keep running. It's very tempting to be snarky about Garoppolo and say "oh yeah, they'll get 80% of that out of literally Mr. Irrelevant in last year's draft," but I don't think I can say that with a straight face. But this is a real downgrade and I think the 49ers pass offense will lose out on some consistency because of it. Shanahan can scheme up the open guys all the same, and those open guys can make moves, but nowhere in his first game did I get the sense that Purdy would deliver the ball exactly where he was supposed to. 

Rivers McCown

Rivers McCown has been writing about football since 2009, most notably at Football Outsiders and covering the Texans for The Athletic. He most recently wrote that thing you just read. He hails from Houston, TX, and has not been traded to Arizona for magic beans yet. You can say nice things about him on Twitter @riversmccown, and you can yell at him on Twitter @RotoPat.