The Seahawks just got upset by a bad division rival at home and now face a big finale against a playoff-bound division foe. Sound familiar?

The same thing happened in 2015. In Week 16, they lost to the 6-8 Rams (Seattle’s offensive line played poorly in that one, too) and then (missing a bunch of key players) blew out 13-win Arizona 36-6 in the finale.

On Sunday night, the Hawks (11-4) will face the 49ers (12-3) for the NFC West title — and they will do so without Chris Carson and Duane Brown (and previously injured Rashaad Penny, Justin Britt and Will Dissly) and also still might be without defenders Jadeveon Clowney, Quandre Diggs and Shaquill Griffin (though Pete Carroll sounded optimistic about Clowney on Monday).

Marshawn Lynch is returning to replace Carson for a game or two (or however long the Hawks are in the playoffs) — and Lynch certainly could provide a big emotional lift to a downtrodden 11-4 team, even if Travis Homer carries most of the running load.

The Hawks also need to replace C.J. Prosise, and C.J. Anderson and former Seahawk Robert Turbin worked out for the team alongside Lynch on Monday. The Hawks later signed Turbin. Jay Ajayi also just became available, waived by Philadelphia.

Running back moves aside, beating San Francisco (and winning in the playoffs) comes down to a couple of things: Russell Wilson & Co. getting going again, and the defense pulling more takeaways while firming up against the run.

Wilson heard “MVP” chants after throwing 22 TD passes in the first nine games and going over 100 rating in all but one, but he has just seven TD throws in the past six games and has been under 100 rating in five of them. (Needless to say, he will not be MVP.)

As we said before Seattle’s win at Carolina, Wilson & Co. have faced some tough defenses — so some of those struggles were excusable. But the loss to Arizona was not. Against a bottom-dwelling defense, Seattle gained a season-low 224 yards and converted a season-worst 8 percent of third downs (1 of 12). After Carson was injured, Brian Schottenheimer did not make the needed adjustments to help Wilson — few rollouts, misdirection, quick-hitters.

Wilson completed just three passes to receivers. A week after catching eight of nine passes for 120 yards and a TD at Carolina, Tyler Lockett caught one of eight against Arizona. The 12.5 percent catch rate was the worst of his career in the 10 games in which he has had at least eight targets.

The offense’s recent performance doesn’t bode well as the 49ers come to Seattle; the Hawks did not do much against the 49ers in the 27-24 overtime win in November either. All of the touchdowns were set up by defensive takeaways (Clowney played his best game of the season). The Hawks will need more of that this time — and really in any game they want to win.

In their 11 wins, the Seahawks have averaged 2.6 takeaways — getting at least two in eight of the wins. In their four losses, they have averaged .75 takeaways — and been blown out in three of those games.

In the Wilson era (2012 on), the Seahawks have lost six games by double digits. Three of the losses have come this year — two in the past three games. In other words, this defense has not been good (or complete) enough to tolerate a poor game from the offense, especially against good teams (New Orleans, Baltimore, Los Angeles).

That means the defense needs to get some takeaways if the Hawks are going to beat the 49ers — and/or avoid a quick exit from the playoffs.

The unit also needs to start stopping the run better. After 12 games, the Seahawks ranked eighth in run defense (99.6 yards per game), but they have given up 186.7 the past three games (162 vs. the Rams, 145 vs. Carolina and, without suspended Al Woods, a whopping 253 vs. Arizona) and now rank 23rd. That’s a bad trend.

But here’s a positive trend: Wilson is 7-0 at home vs. the 49ers.

And he thinks he can make it 8-0. As he said Sunday, “The adversity is temporary. There’s so much to figure out, but I don’t think there’s anyone better than us to figure it out.”