Why Keith Reaser Is the San Francisco 49ers' Best Bet to Start at Cornerback

This is about the San Francisco 49ers’ No. 2 cornerback.

No need to discuss the No. 1 cornerback. That’s Tramaine Brock, period. He missed 13 games last season due to toe and hamstring injuries, but when healthy, he’s one of the best corners in the NFL.

No need to discuss the slot cornerback, either. That’s Jimmie Ward, the Niners’ 2014 first-round draft pick. He was the Niners’ starting nickelback as a rookie last season, and he will be their starting nickelback next season as well.

So who should be the 49ers’ right cornerback? Who should start opposite Brock in the base defense? Here are the top four candidates in ascending order.

4. Chris Cook, Sixth Season

Billy Hurst/Associated Press

Chris Cook, 28, has started 29 games in the NFL, so he’s certainly a candidate to start at right cornerback.

He was the starting right cornerback last year during OTAs and minicamp while starter Chris Culliver recovered from a knee surgery. And even though Cook lost the job to Culliver, Cook played well in training camp and intercepted two passes during the preseason.

But he tore his hamstring in Week 7 and missed the rest of the season. In total, Cook played 48 snaps in 2014.

In 2013, Cook missed time due to groin and hip injuries. In 2012, he missed time due to a broken arm, a stinger and a concussion. In 2011, he missed time due to another groin injury. And in 2010, he missed time due to a torn meniscus.

In five seasons, Cook has played only 40 games for an average of eight per season. He’s injury-prone and should come off the bench.

3. Dontae Johnson, Second Season

Fourth-round pick Dontae Johnson started the final three games at right cornerback last season.

He played well in his first start, giving up just two catches for 16 yards, according to Pro Football Focus. But over the following two starts, Johnson gave up 13 catches for 188 yards and two touchdowns.

Johnson played much better in the slot earlier in the season. In the slot, he allowed a passer rating of 88.1, per Pro Football Focus. When he played outside, he gave up a passer rating of 110.1.

Johnson continued to struggle outside during OTAs and minicamp this offseason, giving up more separation when playing near the sideline than any other cornerback on the team.

Johnson played safety in college, so it makes sense that he seems more comfortable in the middle of the field. His best position might be slot cornerback in the red zone, because at 6'2", he’s three inches taller than Ward.

2. Shareece Wright, Fifth Season

The Niners made Shareece Wright the second-highest-paid cornerback on the team when they gave him a one-year, $2.95 million contract this offseason.

The contract suggests the Niners view Wright as a starter, which is what he has been the past two seasons, starting 27 games since 2013. Last season, he started 14 games for a San Diego Chargers defense that finished fourth in the NFL against the pass.

That’s what’s good about Wright.

Here’s what’s not so good: He committed 13 penalties in 2014—almost one per game. And he gave up a passer rating of 95.5, according to Pro Football Focus, which gave Wright an overall grade of minus-16.8—fourth-worst in the NFL among cornerbacks last season.

The Niners can live with Wright in the starting lineup, but they would probably rather see a young cornerback assert himself and beat out Wright.

1. Keith Reaser, Second Season

Wright missed OTAs and minicamp with an undisclosed injury, allowing second-year cornerback Keith Reaser to play with the first-team defense.

Reaser, the younger cousin of late All-Pro safety Sean Taylor, didn’t play his rookie season—he tore his ACL his senior season at Florida Atlantic University. Even with a torn ACL, the Niners drafted him in the fifth round, which gives you an idea of how good he can be when healthy.

I hadn’t seen Reaser in person until this offseason, when I watched him practice six times—three times during OTAs and three times during minicamp. I saw him give up one catch to Quinton Patton on Day 2 of minicamp, but I didn’t see Reaser give up any other catches.

I did see Reaser break up two passes and intercept two more. The first time starter Colin Kaepernick targeted him during minicamp, Reaser picked him off. Quarterbacks didn’t test Reaser much after that.

Reaser runs a 4.3-second 40-yard dash, according to Mike Mayock of NFL.com. Reaser’s strength is mirroring receivers in man coverage, and he can cover outside or in the slot.

So far this offseason, Reaser has played right cornerback, left cornerback and slot cornerback. His versatility is key, because the Niners seem to be considering playing Brock at different spots, not just the left side of the field, according to Matt Barrows of the Sacramento Bee.

“There has been talk that [Brock] will follow the opponent’s best wide receiver all over the field,” Barrows wrote. If Reaser starts, his versatility will allow the Niners to play Brock wherever they want.

Reaser should start at cornerback in 2015.

All practice observations obtained firsthand unless otherwise noted.

Follow @grantcohn.