What Aldon Smith's Return Means for Battered San Francisco 49ers Defense

The San Francisco 49ers remain in the NFC playoff picture despite dropping two of their last three contests. However, the 49ers will likely need to go on a late-season run in order to move up from their current position (No. 8 seed in the conference) and into a playoff slot.

One reason to believe that San Francisco can go on a late run is the looming return of star pass-rusher Aldon Smith.

Smith, who was suspended for nine games for violations of the substance abuse and personal conduct policies, has been reinstated to the active roster and is expected to make his 2014 debut on Sunday against the New York Giants.

His return could hardly come at a better time for the 49ers defense, which has been forced to operate without a number of key players this season.

Along with missing Smith, the 49ers have been without star linebacker NaVorro Bowman all year due to his ACL tear last year. According to ESPN's Adam Schefter, there is a good chance that Bowman won't be returning this season either. 

Rookie safety Jimmie Ward was placed on injured reserve in order to make room for Smith on the roster. Also, the team will be without defensive tackle Ian Williams this weekend, and cornerback Tramaine Brock is listed as questionable. 

Against the Giants, the 49ers will have one of the league's better young pass-rushers back in the lineup. 

Smith has racked up 42 sacks over the past three seasons and notched 8.5 sacks last year despite making just eight starts. According to Pro Football Focus (subscription required), he created 55 total quarterback pressures on 289 pass-rush attempts in 2013. This means that Smith affected the opposing quarterback 19 percent of the time—or on roughly one in five attempts—when rushing.

According to Kieran Darcy of ESPN New York, Smith's 0.98 sacks-per-game average is the highest of any player with at least 40 games since sacks became an official NFL statistic. 

In other words, Smith is very, very good at generating pressure on opposing signal-callers. 

The ability to rely on a dedicated pass-rusher of Smith's caliber will make any defense better regardless of personnel. Generating a consistent pass rush will ease the burden of the secondary. Being able to consistently do it with one or two star players lessens the need for complicated blitz packages and risk-reward schemes. 

Given the fact Smith hasn't played in a regular-season game this year, we may expect a little rust. We also might expect Smith to play on a limited basis as the 49ers ease him back into action.

The Giants, however, are expecting neither.

"He's conditioned and studied and been in meetings with the team throughout. I don't think there's any doubt that he's ready to go, they'll have him in," Giants coach Tom Coughlin said, via ESPN New York. "He's a very, very good pass-rusher obviously." 

The Giants have plenty of reason to be concerned with Smith. According to Pro Football Focus, quarterback Eli Manning is ranked 28th in the NFL among quarterbacks when under pressure. He has completed just 35.6 percent of passes under pressure this season.

This is a matchup that favors the 49ers. Smith's ability to get into the backfield will likely draw a lot of double-teaming, which will obviously affect the Giants' game plan.

After New York, San Francisco will face another favorable game against the Washington Redskins. After that, however, the 49ers face a tough stretch that includes games against the Arizona Cardinals and San Diego Chargers and two games against the Seattle Seahawks.

The good news is that Smith should be back up to speed by then, and the San Francisco defense should more closely resemble the one that harassed quarterbacks with regularity a season ago.