Examining 49ers defense as camp finishes (w/video)

The 49ers are in their fourth week of training camp. Some positions are beginning to take shape. Others remain cloudy. Here's where things stand on defense as the team returns home from six days in Maryland.

Defensive end

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 imminent 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 easily the best depth they've had at the position under Jim Harbaugh. The question now becomes: If everyone's healthy, who is active on game days? Another cup-runneth-over issue is that Smith is signed through next season while McDonald is signed through 2016. When do the youngsters get a chance to sign 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 would need to make it through waivers to do that. Reportedly, his ankle injury is not long term. It will be interesting to see if it 'lingers' beyond final cut-down day on Aug. 30. Demarcus Dobbs' spot on the roster also seems tenuous with three younger, bigger players vying for playing 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

No one has seen Williams practice since early September, and he 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.

Outside linebacker

There's only been once change since the spring at this position. 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 USF. He must add to his array of pass-rush moves. Right now his bull-rush is his go-to option. But he ought to benefit from working alongside Smith, who has been seen offering advice during practice. Still, Lynch is unlikely to have a role early in the season.

Inside linebacker

Though Chris Borland would overwhelmingly 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 at least has been practicing alongside Patrick Willis all offseason. Borland flies around the field like a pinball but doesn't always find his mark. He's still picking up the defense, of course, 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 decidedly better candidate for 'Mike' inside linebacker, which ends up making the bulk of the tackles. As it stands now, 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 Vic Fangio must figure out is the best combination of 'Mike' and 'Jack.' That is, it may be that moving Willis back to 'Jack' and allowing Borland to play 'Mike' ultimately is the best decision. Bottom line: There are a lot of combinations to consider.

Cornerback

One starter, Tramaine Brock, has been out with an ankle injury since July 27 while the other, Chris Culliver, has practiced sporadically of late as a precaution due to his recovery from an ACL injury. Both have looked sharp, especially Brock, who is an aggressive ball hawk and who is 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. However, he played scant snaps in Thursday's game, then sat out Sunday's and Monday's joint practice.

The flip side is that the 49ers' backups have received a lot of repetitions against top competitions and there is plenty of optimism about them. Perrish Cox seems slimmer and quicker than he's been in the past. Chris Cook, meanwhile, has focused on improving his ball skills and as a result has had plenty of interceptions in practice. Rookie cornerbacks usually start to show improvement at this point in the summer.

Safety

One lingering concern about the cornerback position is how it defends the deep ball. Culliver obviously had problems in that department his first two years in the league while Brock is aggressive and willing to jump routes. Allaying that concern somewhat is the situation at safety. In veteran Antoine Bethea and youngster Eric Reid, the 49ers have two cerebral players on the very back end of their defense, and coordinator Vic Fangio spotlighted the duo for their work in Owings Mills, Md. Bethea may not be as aggressive as the player he replaces, Donte Whitner. There may be no knockout-blow-hit like the one that changed the course of the Saints' playoff game in January 2012. But there also won't be a slew of 15-yard penalties from the safety duo, either.

Behind them, Craig Dahl is not flashy. But he has the coaches' trust and can play both safety spots at a moment's notice. C.J. Spillman, meanwhile, 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 training camp. Campbell has more experience; McCray has more upside.

Finally, first-round draft pick Jimmie Ward has been very impressive in his inaugural offseason despite missing the spring drills with a foot injury. He's precocious, aggressive and while he doesn't make every play, 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.