Weyrauch: NFL Week 1 fantasy football start ’em or sit ’em

Week 1 of the 2021 NFL season is finally upon us. That means it's time to shift from drafting and naming our fake teams to making difficult decisions on a weekly basis in order to win our matchups.

That's where PFF comes in. You'll find sit/start articles from several fantasy analysts each week, and everyone has their own take on what players are eligible for such selections. I'll try to stick with the players giving fantasy managers the most difficult sit/start decisions of the week. 

So let's get to it: the first 2021 edition of fantasy football start ’em or sit ’em.

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Start

QB Matthew Stafford, Los Angeles Rams vs. Chicago Bears

There is a lot resting on Stafford this season, and he gets a great opportunity to prove he was worth the trade haul the Rams shipped to get him. The Bears defense might seem daunting from seasons past, but there just isn’t much to be afraid of outside of Khalil Mack. The Bears lost CB Kyle Fuller this offseason, which left Tashaun Gipson Sr. as their only secondary player with a PFF grade better than 59.5 last season.

Stafford steps into a Rams offense looking to set the tone Week 1. He will chuck darts to the elite tandem of Robert Woods and Cooper Kupp — both were top-16 in targets last season with Jared Goff as their quarterback. One of these two receivers has a stellar matchup to exploit as well, but more on that later.

This matchup carries a market O/U of 47.5 with the Rams favored by 7.5, but the PFF Greenline tool has it as almost a point higher at 48.4 total points and a 7.2-points in the Rams' favor. This gives the Rams a market-implied total of 27.5 points but a PFF implied total of 27.8 points — a top-10 scoring offense on the week. The Rams should have no issues moving the ball against this Bears defense through the air or on the ground, and a multi-touchdown game for Stafford is extremely likely.

RB Raheem Mostert, San Francisco 49ers @ Detroit Lions

Be honest, if you aren’t starting Mostert this week, when will you? He gets an outstanding opportunity right away to beat down on the lowly Lions. The 49ers are tied for the second-highest spread on the week, and that’s with Jimmy Garappollo starting. We will be seeing the patented Shanahan ground-and-pound led by the currently healthy Mostert.

Mostert averaged 11.5 points in 0.5-PPR formats last season when he played more than 40% of offensive snaps. While many think of him mostly as a rusher, he caught at least one ball in every single one of those games — he had two or more receptions in five of six.

Raheem Mostert > Trey Sermon

🗣️ @Ihartitz pic.twitter.com/dlvuFLLxzm

— PFF Fantasy & Betting (@PFF_Fantasy) June 29, 2021

While Trey Sermon does pose a longterm threat to Mostert’s starting gig, the early season — and especially Week 1 — is going to be the Mostert show for the Niners. He is well worth a flex and potentially even an RB2 start in larger leagues.

WR Cooper Kupp, Los Angeles Rams vs. Chicago Bears