Brock Purdy has killed it in San Francisco’s system.
After a strong rookie campaign last year, Purdy has been even better for coach Kyle Shanahan in 2023. By my adjusted metrics, he has an expected 49.1% passing success rate against an NFL average defense, best in the league (42.2% NFL average).
Let’s also look at yards per pass attempt (yppa), as it captures the explosive element of a pass offense. By my adjusted metrics, Purdy is expected to have 8.06 yppa against an average NFL defense. This rating is:
- More than a half yard better than the next best QB (Miami’s Tua Tagovailoa)
- Two yards better than the NFL average.
On a recent episode of The Football Analytics Show podcast, Evan Silva of Establish the Run discussed the trend for NFL defenses to limit explosive plays. The NFL average for yppa has steadily dropped the past four seasons:
- 6.39 yppa in 2020.
- 6.08 yppa in 2023.
Purdy and the San Francisco offense has thrived anyway.
Last week, Purdy struggled against Green Bay, one of the worst pass defenses in the NFL. Still, his numbers were not awful.
- 43.6% success rate (42.2% NFL average)
- 6.28 yards per pass attempt (6.08 NFL average)
- No interceptions, and 2 bad balls on 38 attempts.
They go from facing the 32nd ranked pass defense in Green Bay to the 25th ranked pass defense in Detroit. Better, but still bad.
Against Detroit last week, Tampa Bay had a 46.7% passing success rate and six plays of 20 or more receiving yards. San Francisco has a much better offense.
San Francisco WR Deebo Samuel is questionable to play against Detroit, as he went out with a shoulder injury against Green Bay and didn’t return. Even without the quality of Samuel, the Niners still have plenty of playmakers on offense. Update: Deebo Samuel will play.
Detroit will need an exceptional game from their pass offense. QB Jared Goff and OC Ben Johnson have had an incredible season, and they face the 10th ranked pass defense in San Francisco.
However, Detroit has some critical injuries on the offensive line. Guard Jonah Jackson will not play, and center Frank Ragnow is questionable due to multiple leg injuries.
San Francisco might seem to bring the pass rush from the edge with superstar Nick Bosa. However, interior linemen Javon Hargrave and Arik Armstead have the next two highest PFF pass rush grades after Bosa. This is a bad match up for the injured interior of Detroit’s offensive line.
My numbers have San Francisco by 6.5 points, I don’t think there is any value in a market with San Francisco -7.5.
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