What to watch when Seahawks take on 49ers in Week 15

SEATTLE – The math is simple when it comes to the NFC West for the Seahawks and 49ers Thursday – if the 49ers (9-4) win, they are the division champs.

If the Seahawks (7-6) win, Seattle’s hope remains alive.

But here’s some more daunting math – while Seattle has lost three of four to fall from 6-3 and into second place, San Francisco has won six in a row, the longest active winning streak in the NFL, to go from 3-4 to 9-4 and into a two-game lead.

So, this is truly a tale of two teams heading in opposite directions. Can the Seahawks stop San Francisco’s surge? Or will the 49ers celebrate a division win on Seattle turf for the second time since 2019?

Let’s take a closer look at the matchup with the 49ers with our weekly keys to the game and prediction.

Matchup to watch

Seahawks’ run defense against 49ers’ running game

Here’s the big, obvious, impossible-to-ignore key to this one as a Seattle run defense that has been the worst in the NFL over the past month takes on a 49ers running attack that has been among the more prolific over the past month since acquiring Christian McCaffrey in a trade with Carolina in October. Specifically, the 49ers have rushed for 147.4 yards over their past four games, including 209 in a win over Tampa Bay on Sunday, while the Seahawks have allowed 209.5 rushing yards over their past four games. And with the 49ers apparently going with rookie Brock Purdy at quarterback – but possibly having to give time to journeyman Josh Johnson if Purdy’s oblique injury acts up – the 49ers can be expected to run early and often until the Seahawks show they can stop it, if they can.

Players to watch

Tackles Charles Cross and Abraham Lucas

A San Francisco defense that has allowed just 64 points in its past six games is led by rush end Nick Bosa, tied for the lead in the NFL with 14.5 sacks. The tricky part is that Bosa is equally effective on the left side or right, and outside or inside. But Seattle’s rookie tackles, who have generally held up well in pass protection, figure to each get their shots at Bosa and will need to keep him off Geno Smith as well as they can. “Yeah, they’ll move him around especially in those known passing scenarios and those rush plans they have going with him,” Seattle offensive coordinator Shane Waldron said. “He’ll rush inside, outside, left, right. He’ll do it from a little bit of every position.”

Coaching decision to watch

Running the ball

Seahawks coach Pete Carroll set the template for this game Monday when he reviewed Sunday’s loss to Carolina when Seattle had just 14 rushing attempts, tying a season low also set in losses to the 49ers in Week 2 and Tampa Bay. “We need more turns,” Carroll said. “We need to run the ball more.”

Of course, you can only really run it if you are successful at it and don’t fall behind early, each of which were issues last week. The Seahawks had just 3 yards on four first-down carries in the first half that weren’t by Smith, which makes it hard to keep with it. The 49ers are the toughest team in the NFL against which to run, allowing just 3.4 yards per carry and no more than 67 to any of their last six opponents during a six-game winning streak.

Still, expect Seattle to try this week especially with rookie Kenneth Walker III appearing on track to return after missing last week with an ankle injury. Walker may not be 100%, but his ability to turn nothing into something is something Seattle has missed of late.

The X-factor

Seahawks’ desperation

Because of the seventh playoff spot in each conference, and that the NFC East is going to spend the rest of the month beating up on each other, Seattle’s postseason odds are still OK. But any shot at the division means essentially winning out at this point, which can only happen by beating the 49ers. And even if playoff odds seems OK in the big picture, a loss to the 49ers and then heading to Kansas City sets up the prospect of being 7-8 heading into the last two games – hardly a real base of optimism to build on. Seattle has lost three of four and its last two at home and needs something good to happen fast – and needs to play like that against the 49ers.

Player who could surprise

Cornerback Michael Jackson

If the Seahawks can force the 49ers to throw it some – admittedly, a big IF – then maybe there will be a chance for the defensive backs to catch some errant passes from either Purdy or Johnson. Maybe one of those can land in the hands of left cornerback Jackson, who while being the most targeted Seahawks defender this year at 66, according to Pro Football Reference, does not have an interception this year. Tariq Woolen, in contrast, has six picks in 48 targets this year, via PFR. Woolen, in fact, is the only Seattle corner with an interception this year. This feels like a good game for that to end.

Key stat

First-quarter scoring

After allowing just 38 points in the first quarter of their first 10 games combined, Seattle has allowed 27 in the past three, and at least seven in each, and falling behind in the first quarter of each of the past two games. The Seahawks were able to rally against the Rams in L.A., but not last week against the Panthers. That sounds like a dangerous strategy against the 49ers and their stingy defense – and especially with the conflicting directions of these two teams .

Prediction

49ers 21, Seahawks 13: San Francisco’s QB uncertainty might open a door for the Seahawks, as does the loss of Deebo Samuel. But the 49ers still have the best defense in the NFL – and also against the run – and if the Seahawks can’t run it any better than they have the past few weeks, it’s hard to see them winning this one.