Case Keenum enters the 2018 NFL season with a long list of “firsts” under his belt.

His first big contract. His first franchise quarterback label. His first season starting in Denver. And, come Sunday afternoon at Broncos Stadium at Mile High, a first impression for all of Broncos Country against the Seattle Seahawks.

But dive a bit deeper. In another light, Keenum has done all this before, for better or for worse.

Keenum’s lengthy path to Denver — Texans (2012-14), Rams (2015-16) and Vikings (2017) — included one previous start on Week 1: Rams at 49ers (2016). With the Rams’ first-overall quarterback draft pick, Jared Goff, still developing, Keenum led L.A. out of the tunnel and finished on the wrong end of a rout. San Francisco rolled, 28-0, as Keenum completed less than 50 percent of his passes and tossed two interceptions.

Some might consider the Seahawks a chance for Week 1 redemption. Keenum keeps a different perspective. Different team. New challenges.

“I don’t know if that’s a box I’d like to check. That’s not something I’ve thought about before — winning an opener,” Keenum said. “Obviously, you want to start fast, you want to start the season right being at home. … There’s a lot of reasons to play well and to win. The first game, with it being a season opener, I guess you can add it to the firsts.”

Familiarity might also play a role Sunday, though, taking further consideration into Keenum’s past as he has faced Seattle in three previous games with the Rams. Keenum beat the Seahawks as a starter in 2015 and 2016 with a combined 60 percent completion percentage, 342 yards through the air and one touchdown. Later in 2016, Keenum attempted only nine passes in reserve during a loss at Seattle.

However, much has changed since the Seahawks last hoisted the Lombardi Trophy after the 2013 season. As many as nine new defensive starters will be featured against the Broncos, and most notably, Seattle will play without Pro Bowl defensive backs Richard Sherman (released and signed with the 49ers) and Kam Chancellor (retired). Fellow all-pro Seahawks safety Earl Thomas ended his offseason holdout Wednesday, but it is unclear if he will play Sunday. Seattle’s D is also under the direction of first-year coordinator Ken Norton Jr.

“There is some experience (against Seattle) that helps,” Keenum said. “They’re a similar defense, but they’re a lot different too. … It’s a new challenge, it’s a different offense that I’m in and it’s a different mind-set going in.”

Added coach Vance Joseph: “That defense is more of a culture than it is a certain player. They play hard and they play fast. … As I watch the tape this year, it’s different names and numbers, but it’s the same personalities. It’s Seattle. It looks like Seattle.”

The winning formula Sunday doesn’t require Keenum to be the star. In fact, Joseph prefers Keenum doesn’t.

“Just manage the game for us. That’s the quarterback’s job. We want Case to manage the game and to use his weapons,” Joseph said. “The quarterback’s best friend is running the football and having an efficient pass game to keep the third downs manageable. I want Case to be Case. I don’t want him to be anything special. Just be our quarterback, be a great leader, take care of the football — that’s his job.”

Keenum carries the weight of huge expectations after his surprise heroics — 12 wins, 3,547 yards passing, 22 touchdowns and an NFC championship game berth — for Minnesota. It’s what teammates and coaches reference most when discussing their confidence in Keenum this season. But the sixth-year quarterback prefers to downplay his role in breaking the Broncos’ two-year playoff drought.

Keenum, whether it’s Week 1 or Week 16, keeps the same focus.

“We all want to win. I want to win especially bad, more than a lot of things,” Keenum said. “But I have only so much of me that I can give. Staying within myself, not doing too much, I’ve got a talented, talented offense in there, a talented offensive line, running backs, receivers and tight ends that can make plays for me. I can give them a chance, trust them, let them make plays. If it’s not there, hold onto the ball, take a sack, throw it away and let our defense — we’ve got a great defense …

“Let them make some plays, too.”