49ers Notebook: Life without Brandon Aiyuk; Malik Mustapha trucks and gets trucked; Patrick Mahomes on Maliek Collins’ extra shove

An all-too-familiar story played out for the San Francisco 49ers at Levi's Stadium on Sunday, as they once again wound up not having enough gas in the tank to beat the Kansas City Chiefs.

The Chiefs won their fifth straight over the 49ers on Sunday, this time by the score of 28-18. Each of those five games has been disastrous for the 49ers -- two Super Bowl losses; a 38-27 loss at Arrowhead Stadium in 2018 during which quarterback Jimmy Garoppolo suffered a season-ending torn ACL; a 44-23 blowout loss at Levi's Stadium in 2022; and an ugly defeat on Sunday that had them on the losing side despite holding quarterback Patrick Mahomes to 154 passing yards and two interceptions while also seeing wide receiver Brandon Aiyuk likely suffer the same injury as Garoppolo.

The mood in the 49ers locker room on Sunday wasn't as bleak as it was after their overtime loss to the Chiefs in last season's Super Bowl, but it was still understandably grim.

"Everybody's gonna say that as long as we don't beat 'em, that's something that we gotta take on the chin," linebacker Fred Warner said Sunday. "And, you know, whenever we have that moment to play them again, then it's gonna be the same exact story until we beat them. So that's something that we've got to own. And, hey, you got to take it on the chin."

It's worth noting that the 44-23 loss to the Chiefs in 2022 put the 49ers at the same exact record that they have now (3-4), and from that point the 49ers went on to win 12 consecutive games before bowing out in the NFC Championship game to the Philadelphia Eagles. But things were looking up at that point for the 49ers, who had just acquired running back Christian McCaffrey in a trade. This year, with McCaffrey currently sidelined due to an Achilles injury and Aiyuk now expected to miss the rest of the season, the vibe isn't as rosy for the 49ers as they head into a Week 8 Sunday night matchup at Levi's Stadium against the Dallas Cowboys.

"We got our ass kicked today," head coach Kyle Shanahan said after the latest loss to Kansas City. "Lots of reasons for it, but those are things that they don't need to sit and think about today. We'll address all those tomorrow. We'll get together, we'll go through the truth of the whole tape, be hard on each other and find a way to put it to bed so we can come out here and make sure we put our best foot forward and find a way to get a win versus Dallas."

We'll dive deeper into the locker room reaction to the loss in this version of 49ers Notebook, which will include some quotes on the loss of Aiyuk, along with rookie Malik Mustapha's reaction being on both ends of some big hits and what Mahomes had to say about an extra shove dished out by defensive tackle Maliek Collins on one particular play. Let's get into it...

Next man up at wide receiver

The last two months have brought peaks and valleys for Brandon Aiyuk, who was the subject of numerous trade rumors while seeking a new contract from the 49ers. Aiyuk, who had a career-year in 2023 (75 catches, 1,342 yards, seven touchdowns), finally got the contract he was seeking in August -- a four-year, $120 million deal that put him among the league's highest-paid receivers. But then, after missing training camp and the preseason due to his contract dispute, Aiyuk got off to a slow start to the 2024 season, catching just 13 passes over his first four games. He broke out of his slump with an eight-catch, 147-yard performance against the Arizona Cardinals in Week 5, then had just two catches in a Week 6 win over the Seahawks before suffering what is expected to be a torn ACL in the loss to the Chiefs. If Aiyuk is indeed done for the season, he'll finish with 25 catches for 374 yards and zero touchdowns.

"It sucks," tight end George Kittle said of Aiyuk's injury Sunday. "You know, I love Brandon Aiyuk, the energy that he brings, what he can do on the football field, routes, catching the ball -- he's an incredible football player."

The injury happened in the second quarter of Sunday's game when Aiyuk took a hit to the knee after making a reception. Video replay of the hit made it immediately obvious that the injury could be bad, and Kittle, who found out at halftime, had a similar reaction to fans who saw the injury as it happened.

"I mean, at halftime when you hear someone say, 'We need crutches in a knee brace,' it's like, ah, fuuu-- shoot," Kittle said. "Sorry. Yeah, I mean, Brandon's a great friend of mine, so it impacts you to an extent, but you have to have the three-foot mindset and just attack what's in front of you and then emotionally deal with it at a later time."

Aiyuk's injury helped contribute to a rough outing for quarterback Brock Purdy on Sunday, who was also without wide receivers Jauan Jennings (hip) and Deebo Samuel (illness). Purdy had one of his worst games as a pro against the Chiefs, throwing three interceptions on 17-of-31 passing with a career-low passer rating of 36.7.

"Obviously just what B.A. does for our offense and who he is and as a teammate and a brother of ours, it's sad," Purdy said. "Wishing him nothing but the best and praying for him. That's my guy."

Fortunately, Jennings and Samuel are expected to be back sooner rather than later, and the 49ers also got a boost this week with the return of first-round draft pick Ricky Pearsall from a gunshot wound. Pearsall and fellow rookie Jacob Cowing, who had his first two NFL receptions against the Chiefs, will be expected to take things up a notch in Aiyuk's absence.

"I think Kyle's gonna scheme some stuff up," Kittle said. "The nice thing is we still have Jauan Jennings, Juice [fullback Kyle Juszczyk], Deebo. We still have guys all over our roster that can make plays. And Jake ran an awesome curl pump today and he's gonna continue to get reps and be forced to grow up. Same with Ricky. They're gonna be forced to grow up and mature really, really fast.

"And, you know, it's kind of on us as veterans in the system to help them along and make sure that they are ready to play in these football games. But, yeah, I mean, you can't really replace, in my opinion, one of the best receivers in the NFL.

Shanahan wouldn't rule out a trade when asked about the possibility on Sunday. But for the time being, the 49ers will need to move forward with Samuel, Jennings, Pearsall, and Cowing, as well as Ronnie Bell and Chris Conley, who saw their share of playing time against Kansas City.

"Obviously we have other guys that can step up and do their job really well," Purdy said. "Ricky, having him back for his first game was awesome. Just seeing him back out there and making cuts and plays, he's a baller too. So, we're really excited for him and for his growth and to bring him with us. We're excited about that and thinking about B.A. and wishing him nothing but the best too. We've all just got to come together as a group, collectively, as the receiver unit and all of us. Guys just got to step up, and they have. That's the nature of the sport, sadly."

Both sides of the truck

Rookie safety Malik Mustapha showed the nation on Sunday why the 49ers have been buzzing about him since making him a fourth-round pick in the 2024 NFL Draft. But at the same time, Mustapha had a "Welcome to the NFL" moment Sunday, courtesy of Patrick Mahomes.

Mustapha made two highlight tackles early in the game, one of them on running back Kareem Hunt...

...and another on wide receiver Xavier Worthy:

But for Mustapha, those plays were overshadowed when he was run over by Mahomes at the goal line in the fourth quarter. Mahomes took off running towards the end zone on a 4th-and-Goal play and delivered a shoulder blow to Mustapha that he won't soon forget.

"I feel like I got trucked later too, so those hits really don't mean nothing," Mustapha said humbly after the game. "They always remember that one play. I just try to do my part. Sometimes I got got. Got to look in the mirror and be better."

Still, there's plenty of reason to be excited about Mustapha, who has been filling in for the injured Talanoa Hufanga and looks like a possible long-term starter at safety for the 49ers.

"He's been playing amazing," Warner said of Mustapha. "You know, I'm really happy with Malik and the way that he's playing. He's earned every bit of all the good stuff that's happening to him. We need him to continue to play good for our defense, for our team."

A throat grab? Or not?

There were those online who thought 49ers defensive tackle Maliek Collins got too aggressive with Patrick Mahomes during one play when he reached out and gave Mahomes a shove near his throat.

But while some people on social media thought Collins did Mahomes dirty, Mahomes didn't feel the same.

"I'm hoping that he didn't intentionally," Mahomes said Sunday. "I don't think he intentionally tried to hit me in the throat. I think he was trying to just push me in the chest there and he's taller than me."

Warner takes the blame

One of the pivotal plays of the game came on a 2nd-and-7 in the third quarter when Mahomes escaped linebackers Fred Warner and Dee Winters before taking off down the sidelines for a career-long 33-yard run. That play led to the touchdown where he plowed over Mustapha to give the Chiefs a 21-12 lead.

Warner regretted not being able to make the tackle on Mahomes, which could have changed the complexion of the game.

"It's a play that I've got to make," Warner said. "I'm leaving my coverage to try and make a play and I'm right there. Got to make it. And obviously we know rush lanes and all those sort of things, and then even then we can't let them continue to run down the sideline, those sort of things."

The run was one of the ways Mahomes was able to burn the 49ers despite having an off day through the air.

"He's just running and I'm going from left to right, I'm man coverage on the running back and trying to come off and make the play, so I just didn't make it," Warner said. "That's all it is."