SANTA CLARA — The San Francisco 49ers just lost 12-6 to the Los Angeles Rams. Here are the 49ers’ grades for this performance.

QUARTERBACK: F

It was one of the biggest games of Brock Purdy’s career and also one of his worst. With the season on the line, against a defense that gave up 42 points last week, Purdy completed 45 percent of his passes, averaged a mere 4.5 yards per throwing attempt and threw an interception in the red zone with the game on the line. He crumbled under the pressure of the moment. And he can’t blame the rain. He simply played poorly. He underthrew a deep pass to George Kittle that should have been a touchdown. He missed a deep throw to Ricky Pearsall that should have been a touchdown. And he airmailed a deep pass intended for Jauan Jennings that got intercepted. In Purdy’s last 18 starts, his quarterback rating is 91 and his win-loss record is 9-9. The league has caught up to him. The 49ers better not give him more than $35 million per season. And they better draft a quarterback.

RUNNING BACKS: C

Isaac Guerendo wasn’t spectacular, but neither was Rams running back Kyren Williams. Both of them ran hard, though. The difference is the Rams ran the ball 38 times and the 49ers ran it just 19 times. Which means McVay stuck with the run in a tight game while Shanahan abandoned it. More on Shanahan in a minute.

FULLBACK: F

Ran around a lot but never touched the ball.

WIDE RECEIVERS: F

Jauan Jennings caught just 2 of 9 targets — he was a non-factor. Ricky Pearsall caught one pass and was open deep for another one but Purdy missed him. It’s too bad the 49ers didn’t throw to Pearsall more often. Instead, they threw seven passes to Deebo Samuel, and he caught just three of them, gained 16 yards through the air and dropped what should have been a touchdown catch. Which means it was a typical game for him. He can’t be on this team next season.

TIGHT ENDS: B

George Kittle had 7 targets — the same amount as Samuel. The difference is Kittle gained 61 yards. If only some of Samuel’s targets had gone to Kittle.

OFFENSIVE LINEMEN: C

They gave up three sacks and didn’t create much room to run.

DEFENSIVE LINEMEN: D

They defended the run well enough until the fourth quarter, but they never sacked Matthew Stafford.

LINEBACKERS: A-MINUS

Fred Warner finished with a whopping 15 tackles. Dre Greenlaw had eight in the first half alone — he was phenomenal in his first game back from an Achilles tear. But in the second half, he injured his knee and left the game, and the 49ers turned to De’Vondre Campbell to replace him. Unfortunately for the 49ers, Campbell refused to play, so they had to finish the game with just two linebackers, which is a big reason the 49ers couldn’t stop the run in the fourth quarter. The 49ers almost certainly will cut Campbell. In retrospect, he never should have been on the team. And he’s symbolic of the 49ers’ larger issues this season. They have a bunch of new faces who never came together.

DEFENSIVE BACKS: A-MINUS

They gave up just 160 yards and zero touchdown passes, so you can’t blame them for the loss. Still, they dropped a few potential interceptions that could have swung the game in the 49ers’ favor.

SPECIAL TEAMS: B-PLUS

Jake Moody made both of his field-goal attempts — he was locked in. But this group also committed two illegal formation penalties.

COACHES: F

Kyle Shanahan seemed more interested in placating Deebo Samuel than winning the game. From the first snap, the entire game plan revolved around Samuel simply because he complained on social media this week about not getting the ball enough. Shanahan rewarded Samuel’s poor behavior, and Samuel responded by having another dreadful performance. The 49ers have lost so many games this year simply because they called too many plays for Samuel. That’s essentially how they lost the Super Bowl as well. He had 11 targets and only 3 catches in that game. Shanahan is a Deebo enabler. And with the game on the line, one of Shanahan’s players quit on him and the team. Meanwhile, no one quit on Sean McVay today. His team was together while the 49ers were not. And while Shanahan called 19 runs and 31 passes, McVay called 34 runs and 31 passes. McVay isn’t the greatest coach of all time, but he’s clearly better than Shanahan, who was flat-out terrible this season. If he’s not willing to cut Deebo Samuel, the 49ers need to get rid of both of them. They’re has-beens.