Sit Marcus Mariota. Yes, even in a two-QB league. This is the rare story where my whole disposition has nothing to grab onto — the win over Seattle is real, and it does nothing for your lineup.
Start with what actually happened, because it was mostly good football. Mariota completed passes, his team beat the Seahawks, and he did it with a ruthlessly narrow distribution: 53.3% of his passes went to Stefon Diggs or Terry McLaurin. That is a quarterback who knows where his answers live. As a football watcher, I'll take it.
As a fantasy manager, that's the entire problem. A two-man funnel is a beautiful thing — unless you're holding the guy doing the funneling. Under 6.0 yards per attempt means the completions aren't buying you yardage, and the chunky per-completion bonuses that prop up streamers aren't coming. Five carries for 11 yards is the other shoe. When a quarterback's rushing line is a rounding error, he has to win through the air, and this profile doesn't win through the air in fantasy terms.
So the call is easy and I'm committing to it. Mariota sits in 1QB. Mariota sits in superflex. Mariota sits in your deep-league emergency spot, because you can stream a quarterback with a real rushing floor or a real downfield profile off waivers, and you cannot stream the 53.3% funnel away from Diggs and McLaurin.
The progress inside this box score belongs to them. Diggs and McLaurin are eating a majority of the passing volume, and that's the part of this game I'd act on — both are starts, and if you were nervous about either one's role, this game is your reassurance. Mariota is the engine, not the beneficiary.
What changes my mind: a week where the target concentration thins out to a third or fourth option and the yards per attempt climb. Volume spread plus downfield aggression is a different quarterback. Until I see both, the win is his and the fantasy points aren't.
Start Diggs and McLaurin. Sit Mariota. That's the whole read.

