Today, Andy Benoit completes his marathon tour of 32 team previews. The final team is the 49ers, his pick to win the N.F.C. West. A complete look at Andy’s work this summer is available here.

Imagine how different the N.F.L. could be right now if Kyle Williams hadn’t muffed that punt in overtime of the N.F.C. championship game. The San Francisco 49ers might have gone to Super Bowl 46. Coach Jim Harbaugh would practically be a folk hero. Not only would the firm-jawed 48-year-old have achieved a level of success few college-turned-pro coaches have ever achieved, he would have done so in his debut season as an N.F.L. coach. And with no off-season to install his program. And with a game-managing quarterback!

That’s what makes this whole thing interesting. Had Williams held onto his second fumble that day, we wouldn’t be sure that you have to have a potent passing attack and a superstar quarterback to reach the top of the mountain these days. The Niners would have gotten there the old-fashioned way: by running the ball and playing defense. There would have been nothing fancy about any of it. Their ground game consisted of inside power runs out of basic two-backs and/or two-tight-end sets. The trickiest thing they did offensively was send an H-back in motion for backside blocks.

Defensively, this wasn’t (and isn’t) a crafty or innovative unit. It’s just a supremely gifted one. The front seven is the most assertive, tenacious, fundamentally sound group in the league. The back four has corners who play fervid man coverage and rangy safeties who fly around.

The Niners won 14 total games last season. Was it because of their refreshingly classic style? Or was it because they played in a watered-down division and managed to capitalize on a few nice bounces of the ball? They had a league-best plus-28 turnover differential in 2011. That’s commendable, but history says turnover statistics do not hold from year to year.

Stingy defense and stalwart ground games tend to hold, though. This team appears to be even deeper and more experienced in those areas this season. That doesn’t necessarily mean the Niners resoundingly believe in their old-school formula, though. After all, Harbaugh and General Manager Trent Baalke did make three noteworthy investments at wide receiver: signing free agent Mario Manningham in free agency, signing retired “legend” Randy Moss off the street and drafting A.J. Jenkins in the first round. And, despite what Harbaugh and Baalke say, they also tried to replace that game-managing quarterback with Peyton Manning. In other words, they were willing to reconstruct their entire system.

OFFENSE

Alex Smith has always had shortcomings. He has adequate throwing skills but he’s never been particularly poised in the pocket. He’s uncomfortable with bodies around him. The longer he holds the ball, the less effective he becomes. Part of this is because he has somewhat of a windup motion, which demands extra space and time to deliver throws. A bigger part is Smith simply isn’t instinctive. What makes him markedly smart off the field – an ability to think deep, process information in a detailed manner and analyze – seems to make him mentally slow on it.

This isn’t to say Smith is a bad player. He’s not. But he’s nowhere near what you’d expect from a former No. 1 overall pick. Jim Harbaugh and offensive coordinator Greg Roman are the only coaches Smith has had who truly embrace this. As good coaches do, they adjusted their approach to accommodate Smith’s strengths and camouflage his weaknesses.

When the reads are simplified and the field is fairly static, Smith is a proficient progression passer. Because he’s not comfortable hanging in the pocket for an extended time, the Niners generally limit his progressions to two or three reads. To compare, Drew Brees and Tom Brady usually have up to five reads.

Brees and Brady also have sight adjustments built into their offenses. This means their wideouts run patterns based on how the defense looks. The Niners don’t have sight adjustments. Their routes are called in the huddle and do not change. They’re often fairly simple routes. This is because, with the Niners being a run-oriented team and Smith needing vanilla defensive looks, much of San Francisco’s passing game takes place out of base formations (two backs, two tight ends – run personnel type sets). Base formations are tightly condensed, not spread out. A lot of quick-developing routes require spacing. Think about the short slants that Green Bay throws. Or the one-two-strike! seam passes that Patriots tight ends often catch. These plays come out of horizontally spread formations.

The Niners still have a relatively quick-timing passing game, though. Smith is at his best with three-and five-step drops in which the reads are defined. The problem is, when there are only two or three reads for the defense to eliminate, things can break down in a hurry. This is one reason Smith took 44 sacks last season. He’s so bad at improvising that the Niners sometimes don’t even bother building dumpoff passes or safety outlets into the play designs. Instead, if nothing is open, Smith is told to run or throw the ball away. Instructions like these are what keeps a quarterback’s interception totals down (Smith threw just five last season).

San Francisco’s sacks allowed aren’t solely a function of how Smith is used. This offensive line has to get a lot better. Right tackle Anthony Davis has struggled mightily with body control in pass-blocking since entering the league as a first-round pick three years ago. On the left side, tackle Joe Staley is coming off the best season of his career, but he’s still not dynamic enough to consistently defeat elite pass rushers on an island. Inside, center Jonathan Goodwin doesn’t always play to his 318-pound size when asked to hold ground. At left guard, Mike Iupati is gifted but still prone to mental mistakes – especially when reading blitzes. At right guard, projected starter Alex Boone is better served as a utility backup. That’s why the Niners drafted Joe Looney in the fourth round. The Wake Forest product is said to have tremendous power, but he’ll have to become less top-heavy before he can contribute. For immediate insurance purposes, the Niners also brought in behemoth veteran Leonard Davis.

The key for San Francisco’s offensive line is improving its recognition and chemistry against complex pass-rush pressure concepts. They’ve been awful in this department, which only exacerbates Smith’s weaknesses. To curtail the damage, Harbaugh and Roman call a lot of their downfield shot plays on first-and-10, where defenses rarely blitz and are more susceptible to play-action. The Niners also run religiously on second down in order to avoid third-and-long.

Harbaugh and Niner executives want to change this and develop a more sophisticated passing attack. But they aren’t looking to become the Patriots of the West. Instead, they’re making conservative short-term upgrades. The free-agent pickup Mario Manningham was signed for only two years. Randy Moss is obviously a short-term shot in the dark. First-round rookie A.J. Jenkins, with his modest 6-0, 192-pound frame and polished-but-not-sparkling attributes, seems built to be a system receiver. Same goes for Michael Crabtree. Crabtree, the 2009 first-rounder, has superb body contorting prowess, which allows him to make great short-area adjustments on the ball, but he lacks explosive downfield speed. Durability is also an issue.

The hope is that the 35-year-old Moss can provide a downfield threat. Moss was out of football last season not because of his attitude but because he lost his athletic ability to change direction and throttle down/accelerate. If Moss doesn’t prove to be rejuvenated, Ted Ginn, who has never been a reliable mainstream receiver, will be the only true downfield speedster. Rounding out the receiving unit is Kyle Williams. It’s too bad he’s known for the N.F.C. title game fumbles. In actuality, Williams is a rising young slot weapon with the quickness and skills to also play outside.

The Niners have said they have “six No. 1 receivers” on their roster. This really means they have six Nos. 2 or 3 caliber receivers and will probably be shuffling the starting lineup all season long. No matter how well the wideouts play, tight end Vernon Davis will be the No. 1 target anyway. Davis is uncommonly fast and agile for a 250-pounder with power. He’s also a very good run blocker.

Run blocking from the tight ends is a big element of San Francisco’s offense. Davis and versatile veteran Delanie Walker create a lot of deception and angles simply off designed presnap movement. The Niners also make good use of fullback Bruce Miller’s lead-blocking. And, for as porous as the offensive line is in pass protection, it’s a very good road-grading unit with tremendous size across the board.

Benefitting most from this power scheme is Frank Gore, one of the soundest, most resilient between-the-tackles grinders in football. Gore posted 1,211 yards last season, though he slowed down in November and December. Being 29 and having overcome numerous injuries throughout his career, if the end isn’t in sight for him, it could be just around a blind corner. The Niners know this. They spent a second-round pick on Oregon’s explosive scatback, LaMichael James.

Also, to help handle some of Gore’s short-yardage load, they signed Brandon Jacobs. However, the ex-Giant is starting to fade himself. And even with his freight train size, an upright running style has always made Jacobs an inconsistent power runner. Don’t be surprised if he has less than 50 carries this season. And don’t be surprised if James and Gore both have fewer carries than Kendall Hunter, the fourth (and currently best) piece to San Francisco’s backfield rotation. The fourth-round pick of a year ago has tremendous short-area burst. He also absorbs contact well. The Niners may discover that in Hunter they have an imperfect but respectable replica of Maurice Jones-Drew.

DEFENSE

There’s not a lot of trickery in defensive coordinator Vic Fangio’s 3-4 scheme. Yes, Fangio, like all 3-4 connoisseurs, calls some aggressive blitzes in obvious passing situations. But most of those blitzes are hard for offenses to handle physically, not mentally. And they rarely include more than just one extra pass rusher.

Up front, this D doesn’t get a whole lot more complex than stunting off a four-or-sometimes-five-man rush (the Niners’ defensive line is, by far, the league’s best at executing stunts). On the back end, San Francisco plays a lot of man-to-man with two safeties roaming free over the top. They don’t play quite as much zone or man-free (one safety in centerfield and one in the box) as other teams because they don’t blitz or crowd the box very much. With such a strong front seven, they don’t often need to.

It’s every coordinator’s dream to operate this way. Fangio can do it because his unit is loaded with talent. It starts in the middle, where Patrick Willis and NaVorro Bowman might be the two best 3-4 inside linebackers in all of football. Not two best as in best duo – two best as in one is the best and the other is the second best. Deciding who is 1 and who is 1A is difficult. The kneejerk reaction says Willis is probably No. 1. The sixth-year pro is dynamic and fast attacking in all directions. He’s strong and fundamentally sound in both space and traffic. And he reads the field well. But it’s the third-year man Bowman who lines up on the strong side, where more of the action occurs. It’s Bowman who led the team in tackles last season (Willis missed three games but still averaged about ¾ a tackle less per game than his partner).

It doesn’t matter who is the best, it just matters that both inside linebackers are on the field. (Though, come to think of it, Larry Grant was borderline sensational after he got his feet wet filling in when Willis was out.) What’s special about Willis and Bowman is that not only are they superb against the run, but they’re also both outstanding in coverage. With them on the field every down, the Niners don’t have to make major personnel adjustments in their nickel and dime packages. That makes for a more versatile, stable defense across the board.

One of the personnel adjustment San Francisco did make in nickel last season was replacing starting outside linebacker Parys Haralson with first-round pass-rusher Aldon Smith. Haralson, now on I.R., was a stout run anchor but he didn’t begin to have Smith’s initial quickness and flexibility off the edge. The plan this year is for Smith to be an everydown player. That’s understandable given that he was drafted seventh over all and has more than lived up to it. Outside linebacker Ahmad Brooks brings very valuable versatility to the table.

Smith earned his 14 sacks last season, but he couldn’t have gotten a lot of them without the help of defensive lineman Justin Smith. The relentless 12th-year veteran became the first player to earn All-Pro honors at two different positions (some voters called him a tackle, others an end). Smith does everything well. His greatest skill is eating up blockers on stunts to create pass-rushing lanes for others.

Justin Smith isn’t San Francisco’s only top-shelf defensive end/tackle. On the other side, Ray McDonald has quietly become one of the game’s most athletic, disruptive 3-4 defensive linemen. The sixth-year pro has excellent initial quickness and a knack for shedding blocks and collapsing gaps. With ends like Smith and McDonald, a defense will always have a dominant front line just as long as its nose tackle is capable of holding most of his ground against two gaps. The nose tackle doesn’t even need to be able to collapse the middle or be an immovable roadblock; he simply needs not to get beat. San Francisco’s nose tackle, Isaac Sopoaga, more than meets these requirements. In fact, the 330-pound veteran, being almost as mobile as he is strong, can make regular big plays on his own.

The only concern with San Francisco’s front seven is its lack of depth along the line. Ricky Jean-Francois is a respectable all-around fill-in player, but all the other backups are undrafted fringe guys. The depth in the secondary also isn’t great. If we’re to count nickel corner Chris Culliver as a starter (which we should since offenses these days spend nearly 50 percent of their time in three-receiver sets), then free-agent pickup Perrish Cox can be characterized as the only backup defensive back with any significant experience. And his is fairly short experience. He missed all of last season after starting nine games as a fifth-round rookie for the Broncos in 2010.

If everyone stays healthy, the depth won’t be an issue (remember, with Willis and Bowman, the Niners can use one less defensive back in their sub-packages). Starting corners Carlos Rogers and Tarell Brown are both sound man-to-man defenders. Rogers went to the Pro Bowl last season for his six interceptions and laudable ability to slide inside and cover the slot. Also in the Pro Bowl was safety Dashon Goldson, who has exhibited newfound range and instincts in coverage. The Niners want the inconsistent Goldson to validate his breakout season with another strong performance; instead of giving him the long-term contract he sought in free agency, they applied a $6.2 million franchise tag.

Goldson can be a violent tackler. So can strong safety Donte Whitner. The ex-Bill plays with unabashed speed and energy. He’s not the type of player you build around, but he’s the type who can make big plays when plugged into a stable, star-powered group.

SPECIAL TEAMS

Punter Andy Lee and kicker David Akers are two of the industry’s best. Both can maintain their accuracy when kicking from long distance. In the return game, Ted Ginn is electrifying when healthy. If he’s unavailable, rookie LaMichael James could get a crack on kicks and Kyle Williams will have a chance at redemption on punts.

BOTTOM LINE

The Niners stayed remarkably healthy and got some good breaks with turnovers last season. Even if that luck runs out in 2012, there’s still enough talent and depth here for this team to be contenders in the N.F.C.

Predicted Finish: 1st NFC West

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