Breaking Down The San Francisco 49ers Defense

SAN FRANCISCO, CA - OCTOBER 09: Patrick Willis #52 of the San Francisco 49ers tackles Mike Williams #19 of the Tampa Bay Buccaneers in the first quarter during an NFL football game at Candlestick Park on October 9, 2011 in San Francisco, California. (Photo by Thearon W. Henderson/Getty Images)

In today’s post, I will introduce you to a San Francisco 49ers defense that ranks second in the league in points allowed so far. Of course, it is quite early in the season and allowing only three points to Tampa Bay and eight to the Bengals will average out the fact that they have also given up 23 and 27 to the Eagles and Cowboys, respectively. Still, this is a much improved unit from years past with the addition of first-round pick Aldon Smith and free agent pick up Carlos Rogers, and having guys like Patrick Willis and Justin Smith doesn’t hurt, either.

The 49ers defense is coached by Vic Fangio, who coached the Stanford Cardinal defenses while Jim Harbaugh was coaching there. Despite coaching last season in the college ranks, Fangio actually has quite a bit of experience in the NFL. He broke into the NFL in 1986 as the New Orleans Saints linebackers coach under head coach Jim Mora. The two had spent the three years before that with the Philadelphia/Baltimore Stars of the USFL before Mora was hired to coach the Saints. With the Saints, Fangio developed a number of great linebackers, which included All-Pros Rickey Jackson, Pat Swilling, Sam Mills, and Vaughan Johnson.

After spending eight years with the Saints, Fangio went to the Carolina Panthers as their first defensive coordinator in franchise history. He would have immediate success there, getting his expansion team to rank seventh in the NFL in 1995 and 10th in 1996 before they dipped all the way to last in 1998. Even after that, he would go on to coach the Colts defense for Jim Mora from 1999 to 2001 and the Houston Texans from 2002 to 2005. He would spend a few seasons with the Baltimore Ravens as a defensive specialist before joining Harbaugh at Stanford in 2010.

Now, the Lions will actually be quite familiar with the San Francisco 49ers defensive scheme on Sunday, even though they haven’t faced Fangio recently. His defensive scheme is basically the same thing Dom Capers runs in Green Bay, which is the 3-4 zone blitz defense. The two have had a long friendship and career with each other, as both started out as coaches under Jim Mora with the Stars of the USFL. Of course, Capers hired Fangio to run his defenses both in Houston and Carolina with varying success, but Fangio often didn’t have the pieces to run the style of defense that requires quite a bit of talent.

With San Fran, he has plenty of pieces to work with, including one of the most underrated defensive ends in the league in Justin Smith. Smith had 70 tackles and nine sacks last season from his 3-4 defensive end spot, which is really unheard of. The defense also features rookie outside linebacker Aldon Smith, who already has 3.5 sacks in his first five games in the NFL, and he’s not even starting. In the back four, San Francisco added two new starters in safety Donte Whitner and cornerback Carlos Rogers, who has three picks thus far.

As far as the scheme goes, the zone blitz is a pretty common style for a 3-4 defense to play. It basically means that the defense tries to confuse the offense by blitzing one or more linebackers and dropping a defense lineman into coverage. The idea was initially formulated by 1971 Miami Dolphins defensive coordinator Bill Arnsparger, who placed linebackers in the defensive line to make it look like they were going to rush the passer but pulled them back when the play started. However, the scheme really didn’t become popular until Dick LeBeau started dropping actual linemen into coverage when he was with the Bengals and the Steelers back in the 90s.

I think the most important thing to keep in mind when discussing a zone blitz Defense is that the defense doesn’t always drop linemen into coverage. In fact, most of the time zone blitz defenses use their linemen to eat up blocks and stop the run while using linebackers to rush the passer like other 3-4 defenses. Even when they do drop a lineman into coverage, it is usually to cover a small, shallow zone that can be easily covered by less superior athletes. The following play is what a zone blitz looks like:


In the diagram, the offense is in the same setup from yesterday’s play, where the 49ers scored a touchdown by throwing the ball to Delanie Walker, who is the tight end in the slot. This is basically my way of how I would have prevented that play. In the play, the strong safety comes down and covers the tight end in the slot, while a linebacker picks up the other tight end in the play, Vernon Davis. The defense uses one of the middle linebackers to cover the weakside shallow zone, while blitzing the other middle linebacker up the middle. The key for this blitz is to simply cause confusion about gap and man assignment on the offensive line.

On most plays, the offensive line discusses who is responsible for whom on the defensive line or which gap they are responsible for. More often than not, they don’t expect a 330 pound-ish nose tackle to drop back in coverage while a linebacker blitzes. This split second of pause/confusion by the offensive line, while they figure out what is going on, is often more than enough time for a fast linebacker to take advantage and get in the backfield. A guy like Patrick Willis with his 4.4 speed is perfect for this type of a blitz.

Overall, the Niners defense is a pretty solid one. They have plenty of pieces to work with on the front seven and will be one of the toughest defenses the Lions have faced so far. I think the key will be (like it usually is with 3-4 teams) to make sure that all linemen are blocked. The secondary is good, but you can still take advantage if Stafford has time. All in all, I still expect the Lions to have good day on Sunday and score more than 24 points.

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