Eight games are in the books, giving us a significant sample size to make the following statement: The 49ers' defense is very, very good. The unit leads the league in scoring defense (14.8 points per game), rushing defense (70.8 yards a game) and hasn't allowed a rushing touchdown all season. Here's a player-by-player breakdown of the first half of the season with a look into the future as well.
Madieu Williams, S. No. 20 - Williams had filled in when Dashon Goldson, Reggie Smith and Donte Whitner were, at various points, injured. All three are healthy now, so Williams has been relegated to special teams in recent weeks. Still, when Williams has played, he's played aggressively, signaling that a neck injury that bothered him in Minnesota is behind him. Williams signed a one-year deal with the 49ers in August. Whether he is re-signed likely depends on what the 49ers do with Goldson and Smith, whose contracts also run out at league year's end. On a side note, the 49ers seemed awfully safety-heavy during the preseason. It turns out they've needed that depth. 8 tackles.
Carlos Rogers, CB, No. 22 - Rogers was one of the last cornerbacks remaining on the free-agent market this offseason. A winning team tends to make everyone involved look good, but Rogers's success is real. He may be the best newcomer added to the team. He leads team in interceptions, one of them for a touchdown. He's a smart, veteran presence in the secondary and a genuinely good guy in the locker room. In fact, Rogers won the "Good Guy" award handed out by the Washington D.C.-area media last year. He's the frontrunner for our version, the Garry Niver Award, this season. Rogers is one of the six defensive players - Ahmad Brooks, Justin Smith, Patrick Willis, NaVorro Bowman and Tarell Brown are the others - to play nearly every snap this season. He moves inside to the slot when offenses go with multiple receivers. 20 tackles, 3 interceptions.
Tarell Brown, CB, No. 25 - He's been the most invisible starter this season, and that's a good thing. Brown shook off an early training camp injury, handled the starting job late in the preseason and hasn't let it go. Former general manager Scot McCloughan felt for years that Brown had the potential to be a starter. He's proving McCloughan right this year. Brown is one of the fastest 49ers but also one of the smallest. Still, his tackle total this year shows he is not shying away from contact in the 49ers' aggressive defense. 25 tackles.
Tramaine Brock, CB, No. 26 - Every general manager is trying to find their own Tramon Williams and Sam Shields, the Green Packers cornerbacks who went undrafted in 2006 and 2010 respectively. Brock, undrafted out of Belhaven University in 2010, is the best candidate on the 49ers. He's stronger and more physical than the average cornerback. He won over Fangio before the season and is now the team's No. 4 cornerback. 4 tackles, 2 interceptions.
C.J. Spillman, S, No. 27 - He's mostly been relegated to special teams this year, and is right behind Blake Costanzo in special teams tackles. He's an aggressive and fearless tackler. The 49ers feel that if they can combine those attributes with smarts and experience, Spillman could be a factor on defense in coming seasons. Spillman received a few opportunities to work with the first-team defense early on in training camp.
Chris Culliver, CB, No. 29 - The post-draft review on Culliver, the 49ers' third-round pick, was that he had potential but would need time to round into form after spending most of his college career at safety. Instead Culliver has learned quickly, and he's now the team's No. 3 cornerback. In today's NFL, the third cornerback plays a large percentage of snaps, and that's been the case with Culliver. The seasoning he gets now will pay dividends should the 49ers make the postseason and have to play teams like Green Bay, New Orleans, Dallas and Detroit. Culliver is straight out of central casting for a cornerback. He's tall, long-limbed, athletic and spilling over with confidence. He's taken on the coaching he's received from secondary coach Ed Donatell (whose contributions, by the way, can't be overstated) but is still trusting his instincts so that he reacts quickly to plays. He's a keeper and someone who looks like a starter for years to come. 15 tackles, 1 interception.
Reggie Smith, S, No. 30 - Smith was in a starting role at free safety before a meniscus injury in training camp cost him about a month. Now he enters games when the 49ers go into their dime, or six-defensive-backs, formations. Smith is smart and cerebral, and he has excellent ball skills. However, starter Dashon Goldson is more physical and more aggressive. Smith is one of three safeties in the final year of his contract. 14 tackles, 1 interception.
Donte Whitner, S, No. 31. - While there are questions about free safety moving forward, strong safety is settled. The 49ers signed Whitner to a three-year deal in August, and he has not disappointed. The physical and compact Whitner is at his best near the line of scrimmage, helping in the running game and playing aggressive coverage on tight ends and running backs. Whitner's shortcoming - pun intended - is that at 5-10 he's not great in deep coverage, especially against taller receivers, which is why Goldson usually plays deep. Whitner's aggression also led to the back-breaking catch and run against Dallas in overtime, the 49ers' only loss thus far. 30 tackles, 1 interception
Shawntae Spencer, CB, No. 36 - Spencer is symbolic of the way two people can look at the same subject and come up with two very different interpretations. Two years ago, Spencer was the surprise winner of the starting-cornerback derby, edging out Brown for the job. Then-defensive coordinator Greg Manusky liked Spencer's smooth, clean technique. This year Spencer has lost the war of attrition to other corners. He had a nagging hamstring injury in the summer, then suffered a toe injury during the season. Spencer practiced in full last week but was inactive for Sunday's game against the Redskins. Still, the 49ers have half the season to play, and it stands to reason that they will have more injuries at the position. Spencer is likely to be needed down the line, and he has plenty of experience from which to draw if called upon. Spencer is signed through 2012. 3 tackles.
Dashon Goldson, S, No. 38 - Goldson is the team's top safety. He missed the first two games of the season due to injury, and he seems to be growing stronger and more confident with every game. He has interceptions in each of the last two games. Goldson is exactly what the team wants in a free safety. He can range all over the field and he brings an intimidation factor over the middle. (Just ask Cleveland receiver Greg Little). Despite missing two games, Goldson is third on the team in tackles. Goldson was disappointed in free agency this season as he didn't get the big, multi-year deal he was seeking. So he signed a one-year contract with the 49ers and will try again in March. Once again, he will be an interesting case for San Francisco. Coaches obviously like him. But they have options at the position and they have a lot of other soon-to-be free agents on the roster. 39 tackles, 2 interceptions.
Colin Jones, S, No. 43 - Jones is Exhibit A for the importance the 49ers place on special teams. He only received scant practice repetitions at safety - and even fewer at receiver - in training camp. Yet he has a spot on the 53-man roster, primarily as a coverage player.
Blake Costanzo, ILB, No. 51 - Exhibit B is Costanzo. He's exactly what every special teams coordinator is seeking - someone who's smart, physical, has a magnetic personality and is just a tad crazy. Costanzo is the heart of Brad Seely's special teams. He's another guy whose contract expires at the end of the league year.
Patrick Willis, ILB, No. 52 - Just when you start to hear rumblings that NaVorro Bowman may be just as good as Willis, Willis records a game-high 13 tackles against Washington and forces two fumbles, one of which leads directly to the 49ers' only touchdown of the day. The 49ers are led by their defense, and the defense is led by Willis. The 49ers are his team. He's the one who pumps them up before games and sets the tone during the week. The 49ers have one day off a week - Monday. But if you stop by the team's facility Monday morning, you'll see Willis - and a handful of other veterans - getting in a workout. That's the way Willis, who's not a talker like another No. 52, Ray Lewis, leads. Willis has mentioned on several occasions that he's never played for a winner since joining the NFL. He's on a near-messianic mission this year to end that dubious streak. Willis' tackle totals are down this season because he is being asked to do more on defense, including covering the opposition's tight end, which he's done very well. 67 tackles, three forced fumbles.
NaVorro Bowman, ILB, No. 53 - If Bowman and Willis held a foot race, you'd be hard-pressed to predict the winner. Bowman is just as fast as his counterpart as shown by his ability to corral slippery Michael Vick in a Week 4 win against Philadelphia. The speed of the two linebackers enable both men to stay on the field in all situations, even when the opposition goes with three and four wideouts. The heart of the 49ers defense is its middle, which is why they lead the league in rushing defense and why they haven't allowed a rushing touchdown in 2011. Bowman is a big part of that. 76 tackles (leads team)
Larry Grant, ILB, No. 54 - Grant is stuck behind the best inside-linebacker duo (though Lance Briggs and Brian Urlacher might argue with that) in the league and is relegated to special teams. However, he was impressive in the preseason and likely would be the first man in if either Willis or Bowman were hurt. He's signed through this season.
Ahmad Brooks, OLB, No. 55 - The 49ers took a leap of faith that Brooks, who had only had a bit role as a pass-rush specialist in previous seasons, could hold down a starting job this year. He hasn't disappointed. Brooks has played all but a handful of snaps this season, and he's second on the team in sacks. He's in better shape than he's been since he played at Virginia and he's gaining confidence with every game. Furthermore, he plays a position that's rather threadbare in terms of numbers. Teams like the Steelers and Ravens always keep a full stable of outside linebackers. The 49ers have only three. 26 tackles, 5 sacks.
Tavares Gooden, ILB, No. 56 - He's another fast, physical inside linebacker who teams with Costanzo on the 49ers' coverage units. Gooden once played alongside Ray Lewis in Baltimore, giving the 49ers another option if there are injuries to the star linebackers.
Isaac Sopoaga, NT, No. 90. Sopoaga has received so much press about his fullback role on offense that you forget his presence on defense. He's held up well at nose tackle this season, more than justifying the 49ers' decision not to re-sign veteran Aubrayo Franklin. Sopoaga leaves the game in passing situations. But he promises to have a big role in upcoming games against the Giants, Ravens and Steelers. 8 tackles.
Ray McDonald, DE, No. 91 - His re-signing in August was met with little fanfare. But it should have. (Remember how loudly you - yes, you! - whined that the 49ers weren't being aggressive enough in free agency?) McDonald spent the offseason as if glued to Justin Smith, and the exposure has paid off. McDonald has been Smith's near equal, and the duo has been one of the biggest factors in the defense's solid play this season. McDonald is a big man with a small man's quickness. 13 tackles, 3 sacks.
Ian Williams, NT, No. 93 - Backup defensive linemen must have multiple roles, and Williams officially is a backup at both defensive end and nose tackle. In fact, he saw his most extensive action this year in garbage time in the end of the Week 5 win over Tampa Bay. Williams' natural position, however, is nose tackle. That's where he promises to find his niche in the NFL.
Justin Smith, DE, No. 94 - He's been perhaps the 49ers MVP through eight games and is a perfect fit on a unit that is consistent, hard-working and uninterested in publicity and flash. Smith's forced fumble in Philadelphia is the iconic moment of the 49ers' season. It's hard to overstate what that play did for the 49ers' psyche. 29 tackles, 4 ½ sacks.
Ricky Jean Francois, DE-NT, No. 95 - He's filled in this year at nose tackle when Isaac Sopoaga was out with an infection and at left defensive end when McDonald was out with a hamstring strain. That is, he's one of the team's most valuable backups, and there hasn't been a big drop off when he's in games. Jean Francois is signed through 2012. 9 tackles.
Demarcus Dobbs, DE, No. 96 - Dobbs was a star in the preseason but has mostly has been kept under wraps this season. With Will Tukuafu (wrist) on injured reserve, Dobbs is likely to continue to dress for game days, but he won't see much action unless there are more injuries or lopsided scores. Looking ahead, he will compete with Tukuafu (an exclusive rights free agent) for playing time, if not a roster spot, next year.
Parys Haralson, OLB, No. 98 -- Haralson has been sensitive to all the attention Aldon Smith has received this season. After all, Haralson still is the starter, and he's been solid block in the 49ers' defensive foundation on first and second downs. Haralson was part of the tight-knit group of defenders who worked out together this spring and summer at San Jose State. 18 tackles, 2 sacks.
Aldon Smith, OLB, No. 99 - Smith should be listed as a defensive end as that has been his primary position this year. He enters the game in third-down packages and has rarely been inserted at outside linebacker. In today's NFL, a players who goes in solely on passing downs sometimes ends up playing more than the starter, especially when the 49ers get out to leads in games. Smith has made the most of his snaps. He leads the team with 6 ½ sacks and is candidate for defensive rookie of the year. Sunday's game was the first since Week 4 that Smith did not have a sack. 13 tackles, 6 ½ sacks.
-- Matt Barrows