SANTA CLARA -- With 67 seconds remaining in a late-November game, Jimmy Garoppolo entered for his 49ers debut for the final three plays of another loss.

Garoppolo was on the field at the end of a 24-13 loss to the Seattle Seahawks at Levi's Stadium in 2017, ending on an encouraging note with a 10-yard touchdown pass to Louis Murphy.

“It seems like a lifetime ago,” Garoppolo said. “It’s a great group year-in and year-out. They’re always one of the top teams, and it’ll be a great challenge for us. It’ll be a good atmosphere for us on Monday night.”

Nearly two years later, Garoppolo will make his first career start against the Seahawks in what is likely the 49ers’ biggest game since Levi’s Stadium opened for the 2014 season. The 49ers are 8-0, while the Seahawks (7-2) can close the gap in the race for the NFC West.

“It’ll be fun,” Garoppolo said. “It’ll be a good atmosphere. Levi’s was rocking last time when we played Carolina, and I wouldn’t expect anything less for Monday night. The Faithful will be loud.”

There have been a lot of moving pieces for the 49ers’ offense through eight games, as the club remains the NFL’s only unbeaten team.

Offensive tackles Joe Staley and Mike McGlinchey, as well as fullback Kyle Juszczyk, have missed significant time with injuries. Staley and Juszczyk are expected to return to action on Monday night, and the team is optimistic about McGlinchey’s availability, too.


“It’s always good to get guys back from injury,” Garoppolo said. “I thought those guys who stepped up in their places played phenomenal. It’s football, you never know who’s going to get hurt or whatever. The mixing and matching, I think we did a great job of it while we were in this situation.”

There could be more mixing and matching on the way for the 49ers, too.

Tight end George Kittle was sidelined late in the 49ers’ Week 9 game against Arizona with knee and ankle issues. Kittle did not practice Thursday, and his availability is in question for Monday night.

The 49ers have also had some flux at wide receiver, where they have gotten inconsistent play across the board. The team did not have a go-to wide receiver until veteran Emmanuel Sanders was quickly assimilated into the offense after being acquired in a Week 8 trade from Denver.

In two games, Sanders has 11 receptions for 137 yards and two touchdowns.

“He’s a savvy guy, he feels space in the defense, he’ll cut his route short if he needs to, he’ll take it a little deeper if he has to,” Garoppolo said. “As a quarterback, I love that. Just guys that feel the same thing that I’m seeing and it’s nice having that.”

Through it all, Garoppolo has provided leadership and key third-down completions. Through eight games, Garoppolo completed 70.8 percent of his pass attempts and has a 100.7 passer rating. He has been sacked only 12 times.

“I think having a better understanding of the offense and everything, having an extra year just makes me more comfortable with that stuff,” Garoppolo said.

This is not the same Seahawks defense of the past. Seattle’s pass defense ranks 28th in the NFL, allowing 278.1 yards per game. Only nine of the team’s 15 sacks have come from the defensive line, so the Seahawks are relying more on blitzes.

[RELATED: Carroll misses facing, beating ex-49ers coach Harbaugh]

Still, Garoppolo expects the Seahawks of the past to show up on Monday.

“They start with coverage,” Garoppolo said. “The blitz has shown up more this year and everything, but they’re always a coverage-first team, it seems like. It’s similar to what they’ve done in the past. They’ve had a couple change ups this year with new personnel and everything, but same old, same old.”