San Francisco 49ers

Final week of 49ers training camp: Where things stand on defense

The 49ers began their fourth week of training camp Wednesday. Some positions are beginning to take shape. Others remain cloudy. Here’s where things stand on defense as the team prepares for Sunday’s game against Denver, the first NFL game at Levi’s Stadium:

Defensive end: Nose tackle Ian Williams has been cleared to practice after being sidelined 11 months by a low block and the broken fibula and torn ligaments that resulted from it. It may take Williams time to get up to speed, but his return bodes well for a unit that has been beset by summer injuries. It also allows good-looking second-year player Quinton Dial to concentrate on defensive end, where, at 6-foot-5, he is much better suited.

Justin Smith and Ray McDonald are the unquestioned starters, but Dial, Tank Carradine and Tony Jerod-Eddie give the 49ers the best depth they’ve had at the position under coach Jim Harbaugh. If everyone’s healthy, who is active on game days? With Smith signed through next season and McDonald through 2016, when do the youngsters get a chance and how do the 49ers handle the transition?

With all that depth, it’s hard to see the 49ers keeping neophyte Lawrence Okoye on the 53-man roster. He may be earmarked for the practice squad, but he would need to make it through waivers. Demarcus Dobbs’ spot on the roster also seems tenuous with three younger, bigger players vying for time. He’s always seemed like a better fit for a 4-3 defense, and a smart team will snap him up if he’s released. Rookie Kaleb Ramsey appears destined to spend 2014 alongside fellow draft picks Brandon Thomas, Keith Reaser and Trey Millard.

Nose tackle: Williams will use the rest of the preseason to find the form that made him the starter last year. Williams is not as big and strong as Glenn Dorsey, who is out for an extended period with a biceps tear, but he’s smart, determined and is accustomed to working with Smith and McDonald.

There’s a chance Dorsey gets placed on injured reserve with a designation to return, which means he could play again in 2014 if the 49ers make a playoff push. He will be a free agent at the end of the season. Dial and Jerod-Eddie provide depth. Mike Purcell has been an offseason warrior, but he probably is better suited for the practice squad.

Outside linebacker: There’s only been one change since the spring. Rookie Aaron Lynch looks impressive, and he’s only been practicing in full for about a week. He’s massive, very physical and has long arms – not quite Aldon Smith size, but eye-popping nonetheless – and he’s been a handful for blockers. He looks very much like the guy who played at Notre Dame, not the one who disappointed at South Florida. Right now his bull rush is his go-to option, but he should benefit from working alongside Smith, who has been offering advice during practice. Still, Lynch is unlikely to have a role early in the season.

If Aldon Smith is suspended as expected, the plan is to platoon Dan Skuta and Corey Lemonier in his place. Both performed well in that role last year, and there’s reason to believe they’ll be more effective this year. Skuta, for instance, was dealing with a foot injury; Lemonier was a rookie. Lemonier is stronger and has more experience. He had five quarterback pressures in the preseason opener, according to Pro Football Focus. Ahmad Brooks has been having a strong offseason. If Aldon Smith has been the offseason star for the defense, Brooks is the runner-up. Chase Thomas’ best hope is the practice squad.

Inside linebacker: Though Chris Borland would win a popularity contest among fans and national media, the job of replacing NaVorro Bowman during the first half of the season still belongs to Michael Wilhoite. He knows the defense, doesn’t make mistakes and has been practicing alongside Patrick Willis. Borland flies around the field like a pinball but doesn’t always find his mark. He’s still picking up the defense, and the hope is that when he has a better grasp, his aggressive style will take him to the ball and not just the pile.

Borland is a better candidate for “Mike” inside linebacker, which ends up making the bulk of the tackles. Willis is the “Mike” with the starting unit and Wilhoite is the “Jack,” which has a lot of coverage responsibilities. One of the nuances of this position battle that defensive coordinator Vic Fangio must figure out is the best combination of “Mike” and “Jack.” It may be that moving Willis back to “Jack” and allowing Borland to play “Mike” is the best decision. Bottom line: There are a lot of combinations to consider. Meanwhile, Nick Moody continues to look like the most impressive candidate from a speed and athletic perspective, but he spent a lot of time on the ground in the preseason opener. Shayne Skov has been solid, but the 49ers probably feel comfortable they can stash him on the practice squad.

Cornerback: One starter, Tramaine Brock, has been out with an ankle injury since July 27 while the other, Chris Culliver, has practiced sporadically as a precaution as he recovers from an ACL injury. Both have looked sharp, especially Brock, who is an aggressive ball hawk and the odds-on favorite to lead the team in interceptions this season. It would have been nice to see Culliver scrimmage more against the Ravens since they exploited him badly in the Super Bowl, but he played scant snaps in last Thursday’s game, then sat out Sunday’s and Monday’s joint practices.

The flip side is that the 49ers’ backups have received a lot of repetitions against top competition. Perrish Cox seems slimmer and quicker, and Chris Cook, who has focused on improving his ball skills, has had plenty of interceptions in practice. Rookie cornerbacks usually start to show improvement at this point in the summer, and draft picks Dontae Johnson and Kenneth Acker have made big strides, with Johnson looking like a keeper due to his smarts and size. One oddity/trend: The cornerbacks have become bigger than the safeties.

It would not be a surprise if Brock, Culliver, Cox, Cook, Johnson and Darryl Morris make the 53-man roster, with Acker on the practice squad and Reaser on the non-football injury list.

Safety: One lingering concern about the cornerback position is how it defends the deep ball. Culliver had problems his first two years in the league and Brock is aggressive and willing to jump routes. Allaying that concern is the situation at safety. In veteran Antoine Bethea and youngster Eric Reid, the 49ers have two cerebral players on the back end of their defense, and Fangio praised the duo for their work in Owings Mills, Md. Bethea may not be as aggressive as Donte Whitner, the player he replaces, but there also won’t be a slew of 15-yard penalties, either.

Behind them, Craig Dahl isn’t flashy, but he has the coaches’ trust and can play both safety spots. C.J. Spillman is in his contract season and would love to show other teams that he is a legitimate safety candidate, not just a special-teams ace. If the team wants a safety on the practice squad, it likely will be either D.J. Campbell or undrafted rookie James McCray. Both have flashed in camp. Campbell has more experience; McCray has more upside.

First-round draft pick Jimmie Ward has been very impressive despite missing the spring drills with a foot injury. He’s precocious, aggressive and he always seems to be around the ball. He’s ideal at the nickel cornerback spot where he could play 60 percent or more of the team’s defensive snaps. He’s also been getting repetitions at free safety. That potentially gives the 49ers the option of moving him there and Cox to nickel cornerback if there is an injury to a starting safety this year. Remember, Reid suffered two concussions as a rookie.

Related stories from Sacramento Bee