Week 7 was a chance for the San Francisco 49ers to get their season on track.

They hosted the Kansas City Chiefs in a Super Bowl LVIII with a chance to hand the Chiefs their first defeat of the year and exact at least a small amount of revenge for the Super Bowl defeat.

Instead of getting their season on track, the 49ers face planted spectacularly in a dreary 28-18 loss at home that underscored a bunch of the problems holding this year’s 49ers club back from being a Super Bowl contender.

One loss in Week 7 won’t ultimately define the year, but there were a handful of things that happened in the game that certainly matter when it comes to San Francisco’s quest to be among the NFL’s best teams:

Brandon Aiyuk's injury

The 49ers fear Aiyuk tore his right ACL after taking a low hit late in the second quarter. He limped to the blue medical tent and was carted off the field at halftime. San Francisco doesn’t have a receiver who affects the game and gets open the way Aiyuk does, and losing him may fundamentally change how the 49ers are able to throw the football over their final 10 games. Aiyuk finished Sunday’s game with two catches for 23 yards on six targets.

Bad Brock Purdy

It isn’t time to hit the panic button on Purdy. He has been too good for too long to have one game determine his impact on the 49ers. However, in a game where an elite signal caller could have helped buoy a scuffling offense, Purdy turned in the worst game of his career. He tossed three interceptions and completed just 17-of-31 passes. His accuracy was scattershot, and two of his interceptions were baffling throws into non-existent windows. Even his two long completions to TE George Kittle and rookie WR Jacob Cowing should have been touchdowns, but he underthrew both players and forced them to stop and wait for the ball to come down. It was the worst version of Purdy in a spot where even a mediocre version might have been enough to get the 49ers a win. He has to be better, especially with Aiyuk potentially out for the season.

Rookie WRs play

It’s not nothing that first-round rookie WR Ricky Pearsall and fourth-round rookie WR Jacob Cowing both saw significant action Sunday and had their first receptions in the NFL. Pearsall caught three balls for 21 yards. Cowing snagged two catches for 50 yards, including the 41-yarder late in the game that would’ve been a touchdown with a better throw. Both players bring athleticism the 49ers lack in their receiving corps, and they both figure to see more time with Aiyuk injured. Pearsall showed off some of the toughness over the middle that made him an intriguing prospect. Cowing was used on a screen and on a deep shot that showed off how he can affect the game at different levels. A maximized version of San Francisco’s offense will have to include at least one of the rookies contributing, and they got off to a good start Sunday.

Red zone woes re-emerge

A week after being better in the red zone, the 49ers’ issues inside the 20 were back again. They went two-for-four in the red area, including a dreadful interception from Purdy that ostensibly ended San Francisco’s comeback attempt. It’s clear whatever they need to figure out in the red zone isn’t going to happen until RB Christian McCaffrey returns. And if he doesn’t, touchdowns are going to be hard to come by all year. RB Jordan Mason isn’t as effective in confined spaces, and the 49ers pass catchers don’t separate well enough in the red zone where there’s less room to operate. Scheme matters, but players have to execute and win their reps and San Francisco isn’t doing that often enough in that area of the field.

Another special teams miscue

Playing from behind isn’t the way to beat this iteration of the Chiefs. The 49ers fell behind 7-3, and then punted on their next possession. That punt was returned 55 yards to San Francisco’s 30, setting up a short touchdown drive for Kansas City that put them ahead 14-3 and forced the 49ers into a tough spot against an elite defense. This marks the sixth consecutive game where a special teams mishap has plagued San Francisco in some way.

A change at LB?

The 49ers spent a lot of time in their base defense with three linebackers on the field against a Chiefs offense that ran a ton of multiple tight end sets. In the second half they spent more time in nickel packages, but it was Dee Winters alongside Fred Warner instead of De’Vondre Campbell. Typically Campbell has been the every-down player for the 49ers at the Will LB spot. Winters was getting sprinkled in a little there before Sunday to add some athleticism in the second level. We may have seen him take over that spot for good in Week 7.

This article originally appeared on Niners Wire: 6 things that mattered in 49ers demoralizing loss to Chiefs