Since 1986, he's been coaching NFL defenses. He started as the defensive backs coach with the New Orleans Saints before becoming defensive coordinator for the Pittsburgh Steelers. He was the first head coach of the Carolina Panthers and has been a special assistant to the New England Patriots. When looking at NFL resumes, his is one of the best.
So why can't he stop a mobile quarterback?
The Packers have been abused by the new breed of NFL quarterback since that trend took hold. If you consider the 2012 season the first year of the mobile quarterback who runs and passes, the Packers' record is not pretty.
This is a stark contrast from Capers' early success with the Green Bay defense. When he took over the team's defense in 2009, the Packers had just finished ranked No. 21 overall. He quickly pushed them up to a No. 2 ranking.
The following season, 2010, they finished No. 2 in scoring defense, No. 5 in total defense, No. 2 in interceptions and No. 2 in sacks. When the Packers won the Super Bowl after the 2010 season, it was not just because of Aaron Rodgers but because of an aggressive, opportunistic Capers defense.
And then it started falling apart.
Charles Woodson got injured and older and has now left town. The three-man defensive line has never been as good as it was during the Super Bowl run—especially with B.J. Raji's career doing some kind of Benjamin Button act. Talent is essential, but schemes are too. And both have been a problem as the Packers face mobile, attacking quarterbacks.
What are the problems?
1. Poor in-game adjustments
In the 2013 season opener, the Packers expected the San Francisco 49ers to come out and run the read-option all day—just like they had in the divisional playoffs the year before. They didn't.
Instead, Jim Harbaugh's team came out in formations and personnel packages that indicated a running-based offense, but the 49ers instead threw the ball for more than 400 yards. There were no in-game adjustments once they had showed their hand. Instead of switching to a man coverage, Capers' defense sat in a loose zone designed to allow defenders to keep their eyes on the running threat of Colin Kaepernick.
Would a man coverage have worked? Maybe, maybe not. But it would have eliminated plays like the one shown here.
The 49ers come out in a power running formation. The Packers get aligned accordingly.
Before the snap, Kaepernick signals a shift. This spreads the 49ers' formation out, with five targets distributed away from the offensive line. Even tight end Vernon Davis is flexed out in the slot on the top of the image. This is the opposite of power football as the empty-backfield look spreads the field.
The Packers' adjustment is not a good one. They're now in a defense with a single high safety (circled in yellow) and with outside linebacker Clay Matthews covering slot receiver Kyle Williams. Matthews is an exceptional pass-rusher, but he should never be in coverage on an obvious passing down.
The result is an easy pitch-and-catch to Davis, who runs a simple hook route once he finds a soft spot in the Packers' zone coverage. Linebacker A.J. Hawk cannot get to the seam in time, and Davis picks up yardage that could have been eliminated had the Packers adjusted to the formation.
You might think that personnel in the huddle on this play would keep the Packers from running their own nickel defense out. The 49ers had one running back, two tight ends and two wide receivers in the huddle, which for some teams may mean a running play. But film study from previous matchups would show Capers that the 49ers shift out of this personnel grouping often. He's forced to play the odds here, and in a base defense, his men couldn't keep up.
2. No inside pressure
You might think that to pressure a mobile quarterback you need to send both outside linebackers in a 3-4 defense to attack the edges. That's not true at all.
The best way to pressure a mobile quarterback is right up the middle, and the Packers have struggled to do this with their three down linemen and two inside linebackers.
Former top-10 pick B.J. Raji was supposed to be the team's version of Vince Wilfork, but his inconsistency and struggle to use his hands to beat blockers have kept that from becoming a reality. Instead, you have a team with a good outside presence but no inside penetration.
Let's take a look at Week 5 of the 2012 season. The Packers went to Indianapolis to take on rookie quarterback Andrew Luck and the Colts. This was a Colts team with a poor offensive line, a rookie quarterback and not much of a run-game threat. This should have been a cakewalk for the Packers' secondary and linebackers.
Luck completed 31 of 55 attempts for 362 yards, two touchdowns and a fourth-quarter comeback win.
Here are a few takeaways from the raw data. Luck wasn't pressured on 38 of his 62 dropbacks, but the Packers blitzed on 30 (almost 50 percent) of snaps. That shows a team that's overly committed to the blitz in order to get pressure. And even when blitzed, Luck completed 15 of 28 passes for 201 yards and a touchdown.
The Packers were able to sack Luck four times in the game, with three of them coming off the blitz. When you blitz a mobile quarterback, he has more options than "just" the throw. Luck showed with his footwork and agility outside the pocket (six runs for 24 yards) that he's capable of beating you if you overcommit pass-rushers on the edge.
Why does inside pressure work so much better? Even the best outside pass-rushers are at a disadvantage. It's simple physics.
An edge rush is coming at the quarterback from the side. If that quarterback is able to step up, the pass-rusher must adjust his angle and his landing point—something that's not easy to do when trying to turn a corner at full speed. The quarterback can also step back out of the path of the rusher and use his feet to run to the point on the field where the linebacker is coming from.
On the contrary, inside pressure is coming at the quarterback in a straight line. There is no corner to turn, and you have a much shorter path to the passer. If the quarterback steps laterally, the inside pass-rusher can see it and has an easier time adjusting his hips and landing point.
Think about it this way—are you more under control turning a corner at full speed or running in a straight line? Because the Packers are forced to rely on these outside blitzes, mobile quarterbacks are able to get away and make plays with their feet or arms.
Dom Capers is still a quality defensive coordinator. That said, his failure to adjust his game plan and the reliance on an outside blitz will see his scheme become less successful. His defense is built to attack a pocket quarterback, not a 6'5", 240-lb quarterback who can run a sub 4.6 in the 40-yard dash.