Brandon Aiyuk and the 49ers got the worst news possible regarding the receiver’s injured knee on Monday. The star receiver, who signed a contract worth up to $30 million annually less than two months ago, not only tore his ACL but also his MCL — and suffered possibly even more damage in the knee — during Sunday’s 28-18 loss to the Kansas City Chiefs.
The injury ends Aiyuk’s season. The 49ers had feared an ACL tear after the game but needed Monday’s MRI to confirm that damage. It’s far too early for a timeline on Aiyuk’s potential return — the start of the 2025 season is just over 10 months away — but the existence of damage beyond the ACL might complicate matters.
The team also sent receiver Deebo Samuel to the hospital. He has pneumonia. Samuel woke up sick on Sunday morning and struggled to breathe early in the game, so he managed only four plays. He checked into the hospital after fluid was discovered in his lungs.
Here are the grades from yesterday’s 49ers’ loss
Quarterback: Brock Purdy (63 snaps)
Game grade: D+
So much for an epic QB display. Purdy and his Kansas City counterpart, Patrick Mahomes, have been the game’s most efficient quarterbacks since 2022. But they both delivered the worst passer ratings of their careers on Sunday.
Purdy threw three interceptions and finished with a 36.7 rating. Mahomes threw two picks and posted a 44.4 rating. Only Mahomes, though, avoided truly backbreaking mistakes. Purdy failed in that regard. Much of his game is predicated on timing, which certainly seemed misaligned as he played with a large cast of reserve receivers.
Purdy did have some quality runs and he connected on two deep passes, although neither throw was perfect. Ultimately, mass personnel absences in the run game and across the receiving corps proved too detrimental against Kansas City’s aggressive defense.
Running back/fullback: Jordan Mason (54), Isaac Guerendo (5), Kyle Juszczyk (26)
Game grade: C
Outside of a 26-yard run in the first half, Mason managed only 33 yards on 12 carries. He had precious little operating room, though. The Chiefs completely overwhelmed the 49ers’ interior offensive line, especially in short-yardage situations. That led to brutal opportunities for Mason, who actually gained 11 yards over expectation, according to NFL Next Gen Stats. But we can’t award a higher grade for such an inefficient run performance.
Wide receiver: Ricky Pearsall (48), Chris Conley (44), Brandon Aiyuk (25), Ronnie Bell (24), Jacob Cowing (12), Deebo Samuel (4)
Game grade: C-
This one is tricky. Aiyuk had a terrible and possibly game-changing drop in the second quarter. A potentially huge third-down conversion for the 49ers quickly turned into a Chiefs touchdown, thanks in large part to that gaffe. Shortly thereafter, Aiyuk tore his ACL.
That, combined with Samuel’s early exit, thrust young backup receivers — namely Pearsall and Cowing — into new roles.
“We had to mix around a lot of stuff at halftime,” Shanahan said. “Those guys were in spots that they didn’t prepare for. For the most part, they didn’t make mistakes.”
Cowing’s explosiveness shined twice, once on a tunnel screen the play after Aiyuk’s injury and once on a double-move deep reception from Purdy in the fourth quarter.
Tight end: George Kittle (58), Eric Saubert (14), Jake Tonges (1)
Game grade: A
With six catches for 92 yards, Kittle was the 49ers’ top receiver. He’s quietly the key to beating smothering man-to-man coverage, which Kansas City employs — especially when the 49ers are missing their top wideouts. Safeties simply have a very hard time staying with Kittle, as was evident when he burned the Chiefs’ Justin Reid on a 41-yard bomb in the second quarter.
On Monday, Shanahan revealed that Kittle suffered a foot sprain and will be day-to-day this week.
Offensive line: Colton McKivitz (63), Dominick Puni (63), Jake Brendel (63), Aaron Banks (63), Trent Williams (54), Jaylon Moore (9)
Game grade: D-
The 49ers actually weren’t terrible when it came to picking up some of the exotic blitzes that Chiefs defensive coordinator Steve Spagnuolo likes to dial up. But they did suffer pass-blocking losses in key spots, including when Kansas City defensive end George Karlaftis beat McKivitz cleanly with a spin move to force Purdy’s third interception.
Run blocking was a major issue. Brendel’s holding penalty on the game’s second play from scrimmage set a putrid tone for the 49ers, who were simply unable to gain one yard when they needed just one yard. For an offense predicated on balance, that’s a huge structural issue.
Despite the worst passer rating of Patrick Mahomes' career, the Chiefs were able to remain generally efficient — while the 49ers were a train wreck. It starts up front with the avoidance of negative plays that put an offense behind the sticks: pic.twitter.com/TCqdydoE3J
— David Lombardi (@LombardiHimself) October 21, 2024
Defensive line: Nick Bosa (56), Jordan Elliott (44), Maliek Collins (43), Leonard Floyd (42), Sam Okuayinonu (37), Kevin Givens (25), Kalia Davis (22), Robert Beal Jr. (12)
Game grade: B
Here are the 49ers’ pressure totals, courtesy Pro Football Focus:
- Bosa: 5
- Collins: 3
- Floyd: 2
- Okuayinonu: 1
- Givens: 1
Keep in mind that the 49ers were facing one of the best offensive lines in the NFL. The Chiefs rank No. 1 in ESPN’s pass-block win rate and No. 2 in run-block win rate. So it took a solid performance to pressure Mahomes into a his inefficient passing day. The best play came from Davis, who was once an inside linebacker in college. He applied those skills on a spectacular interception that he tipped to himself.
Beyond that, much of Kansas City’s damage on the ground came on misdirections runs to the perimeter — which typically fall under the responsibility of the back end.
Linebacker: Fred Warner (70), De’Vondre Campbell (50), Dee Winters (38), Tatum Bethune (2)
Game grade: C+
Warner couldn’t quite corral Mahomes for a sack on a 33-yard scramble that put the Chiefs in position to seal the game. That’ll be one of the lasting images from this 49ers’ defeat.
Beyond that, Mahomes again found consistent completions over the middle of the field, although he wasn’t nearly as efficient there as when he delivered on 24-of-26 throws in the Super Bowl. Mahomes was 12-of-16 for 112 yards on passes between the numbers, good for a solid-but-unspectacular 7 yards per attempt. The needle didn’t move too far in either direction for the 49ers linebackers.
Defensive back: Ji’Ayir Brown (70), Deommodore Lenoir (70), Malik Mustapha (69), Charvarius Ward (69), Renardo Green (44), Isaac Yiadom (6)
Game grade: B+
It appears that the rookie Green has leapfrogged Yiadom on the depth chart. He saw the bulk of work as the 49ers’ third cornerback. Over 22 snaps in coverage, Green allowed only a 26-yard reception to Chiefs tight end Noah Gray.
Both Lenoir and Ward were good. The former kept up with Kansas City speedster Xavier Worthy and intercepted Mahomes early in the second half. The later broke up a deep attempt to Chiefs tight end Travis Kelce on a key third down.
Mustapha was a missile, especially when he obliterated Hunt in the first half. But the rookie also missed three tackles and was a touch late on Mahomes’ QB draw for a fourth-quarter touchdown. The 49ers are undergoing some growing pains at safety, but Mustapha promises to make them worth it.
Special teams: George Odum led the way with 20 special teams snaps. He, Beal, and Demetrius Flannigan-Fowles all logged a tackle. The 49ers committed yet another big gaffe on special teams. This one came when they allowed a 55-yard punt return to Kansas City’s Mecole Hardman. That led to a Chiefs’ touchdown and a 14-3 deficit for the 49ers.
Fill-in kicker Anders Carlson drilled a 55-yard field goal but he also missed an extra point after missing five of those for the Green Bay Packers last season. Carlson will continue as the 49ers’ kicker against the Dallas Cowboys next week since Jake Moody will not yet be back from his high ankle sprain.
The game ended with Mitch Wishnowsky’s woefully short onside kick attempt. That did a good job encapsulating the 49ers’ entire afternoon.
Game grade: D