San Francisco 49ers Week 4 Stock Report

One San Francisco 49ers player whose stock is down Week 4: defensive end Tank Carradine.

The Niners drafted Carradine with 40th pick in 2013, ahead of standout players such as Carolina Panthers defensive tackle Kawann Short, Pittsburgh Steelers running back Le’Veon Bell and New England Patriots linebacker Jamie Collins.

Carradine was a “need” pick—the Niners needed someone to replace their best player, defensive end Justin Smith, when he retired. Like Smith, Carradine was a 4-3 defensive end in college. The Niners thought he could successfully transition to a 3-4 defensive end like Smith did.

So far, it seems the Niners thought wrong. Smith is gone, and Carradine can’t replace him. He mostly has been a non-factor as an interior defensive lineman—registering zero sacks or quarterback hits the past two weeks, according to Pro Football Focus.

San Francisco probably should move Carradine back to his natural position.

This is the Week 4 stock report.

Stock Down: CB Tramaine Brock

Ross D. Franklin/Associated Press

Considering how poorly Niners’ No. 2 cornerback Kenneth Acker played Week 2 against the Pittsburgh Steelers, it seemed only natural the Arizona Cardinals would try to exploit him Week 3.

But the Cardinals exploited Niners No. 1 cornerback Tramaine Brock, instead. According to Pro Football Focus, Cardinals quarterback Carson Palmer posted a passer rating of 128.0 when targeting Brock’s coverage.

Brock played near a Pro-Bowl level in 2013—his first full season as a starter. But he missed 13 games in 2014 due to various injuries, including a strained hamstring, which continued to bother him this offseason. He still doesn’t seem right.

Stock Up: CB Kenneth Acker

Ross D. Franklin/Associated Press

In Week 2, second-year cornerback Kenneth Acker earned a minus-4.3 coverage grade, second-worst in the NFL among cornerbacks, according to Pro Football Focus.

It was Acker’s second game as a pro—he spent his rookie season on the Injured Reserve list—and he had to cover one of the best wide receivers in the world—Antonio Brown. Acker never had faced anyone that good.

The next week, Acker faced former first-round pick Michael Floyd, who’s not as good as Brown, but still is an excellent receiver. Acker shut him down, allowing just one catch for 12 yards, according to Pro Football Focus, and also intercepted a pass intended for Floyd.

Acker may be the Niners' best cornerback right now. How ironic is that?

Stock Up: CB Dontae Johnson

Ross D. Franklin/Associated Press

As well as Acker played Week 3, Niners No. 3 cornerback Dontae Johnson may have played even better.

According to Pro Football Focus, Johnson was targeted six times, broke up one pass and allowed just one catch for 22 yards to wide receiver John Brown.

Johnson is giving up a passer rating of just 66.9 this season, per Pro Football Focus, while Niners No. 1 cornerback Tramaine Brock is giving up a passer rating of 105.0.

Johnson seems faster and more explosive than Brock through three games. If Brock continues to struggle, the Niners probably should bench him and start Johnson next to Kenneth Acker instead.

Stock Down: Defensive Coordinator Eric Mangini

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Jeff Deeney of Pro Football Focus tweeted this fascinating stat Sunday night after the Niners’ Week 3 blowout loss to the Cardinals: “49ers were in base defense on 7 of the 8 plays AZ used 11 personnel in the first quarter, forcing either a LB or S to line up vs. Fitzgerald.”

So THAT is why Fitzgerald was so open early in the game—he was roasting guys like Ahmad Brooks and Aaron Lynch. Why would defensive coordinator Eric Mangini think those two could cover Fitzgerald, a future Hall of Famer? What an absurd game plan.

Previous defensive coordinator Vic Fangio was a game-planning genius. He game-planned around his players’ strengths, which was one of his best qualities. Mangini doesn’t even seem to know what his players’ strengths are.

Stock Down: QB Colin Kaepernick

Rick Scuteri/Associated Press

Raise your hand if you thought recycled perennial backup quarterback Tyrod Taylor would have better stats than Colin Kaepernick three games into the season.

Check out the numbers:

Kaepernick: 59-of-91 (64.8 percent), 567 passing yards, 2 touchdowns, 4 interceptions, 71.1 passer rating.

Taylor: 58-of-78 (74.4 percent), 714 passing yards, 7 touchdowns, 3 interceptions, 116.1 passer rating.

Taylor is in his first season playing under offensive coordinator Greg Roman. Kaepernick played under Roman for three years and never looked as comfortable as Taylor does now.

The Niners may have to move on from the Kaepernick Project. They almost certainly have to draft a quarterback in the first few rounds next year.

Follow @grantcohn.