The Packers' slow-moving train

Posted by ESPN.com's Kevin Seifert
Mike McCarthy points out how little time the average NFL team spends in its base defense. Ted Thompson insists little will change in the way he evaluates college prospects. Thompson suggests that Aaron Kampman will be on the line of scrimmage with his hand on the ground -- in other words, a defensive end -- on more than half of his snaps.

If you blinked last week at the NFL's annual scouting combine, you might not have remembered Green Bay is shifting to a 3-4 base defense this offseason. The Packers' coach and general manager continued to downplay the change and minimized how visible it might be on a play-to-play basis.

"The 3-4 defense is a starting point for us," McCarthy said, "from a terminology and language standpoint. And we will definitely have the ability to get into 4-3 schemes and even moreso into our sub personnel groups."

At one point, I asked McCarthy how often NFL teams employ their true base defense over the course of the season. His answer: About 150-200 snaps. Over the course of a 1,000-play season -- the Packers had 1,003 defensive snaps in 2008 -- that averages out to about 15-20 percent. On the other 80 percent, teams are in the nickel or a blitz package or some other combination that alters its alignment in some way.

What's with the soft sell? One interpretation: The Packers' shift from a 4-3 to a 3-4 will be gradual. If everything goes well, the defense will look much different in 2010 and 2011 than it does this season.

The Packers aren't going to stand on top of Lambeau Field and announce it, but so goes the reality of changing philosophies after decades of acquiring players to fit the 4-3. It's a sentiment readily apparent even to non-professionals, as we've noted in regular trips to the NFC North mailbag.

During the combine, there were plenty of "football people" who agreed with Ben of Iowa City, who recently wrote:

"I am all in favor of the 3-4 defense. I think you can do big things with it when you have the right personnel. I think the Packers have about half of what they need."

New Lions coach Jim Schwartz, asked if he planned to keep the Lions' 4-3 approach or switch to a 3-4, said:

"[The 3-4] is a completely different skill set -- and not just the linebacker position, which is what everybody sort of sees. It's the noseguard and the defensive tackles and it would probably take a pretty major overhaul."

Pittsburgh director of football operations Kevin Colbert, whose team has run a 3-4 for years, said it takes players a minimum of two years to learn the system. Interestingly, Colbert said the transition is hardest for the "tweener" defensive ends of the 4-3 scheme.

"It's harder for him to be able to project because the ends are going to have to be a minimum of 290 pounds to be able to play in that scheme," Colbert said. "And linebackers are going to have to be able to do certain things in coverage. The 265-270 [pound] end will have the most difficulty."

That point illustrates one of the Packers' central conundrums in making this shift: By Colbert's analysis, the Packers' best defensive player is a poor fit for a traditional 3-4 scheme. Kampman, a two-time Pro Bowl defensive end who has compiled 37 sacks in the past three years, is listed at -- yes -- 265 pounds.

Officially, Kampman will move to linebacker. His position coach will be former NFL linebacker Kevin Greene. But during a meeting with reporters at the combine, Thompson predicted Kampman will spend up to 60 percent of his time as a pass-rusher on the line of scrimmage. Here's how McCarthy put it:

"[T]he scheme will fit Aaron Kampman and the rest of our football players. It's not about taking someone and forcing them to do things that maybe wouldn't be in their best interest on an individual basis. So this scheme will put our players in position to be successful."

There are plenty of 3-4 defenses who use their outside linebackers as almost full-time pass-rushers. (See DeMarcus Ware in Dallas.) But Kampman's situation also speaks to the delicate balance the Packers must strike in this first season of the new scheme.

In some regards, new defensive coordinator Dom Capers is building a transition scheme while Thompson re-aligns the roster. Thompson's primary analysis of players at the combine didn't change -- "Football players are football players at the end of the day," he said -- but added there will be &qu
ot;subtle" differences in the types of players he drafts and signs on the free-agent market.

"There are exceptions and there are ballpark numbers that you want to shoot for," Thompson said, "because historically speaking, your odds are better if you have these type of players at these type positions."

Because most colleges play a version of the 4-3, Thompson and the Packers must now decide whether some defensive tackles can play end in their system. They'll have to evaluate whether a defensive end projects as a linebacker. They'll have to avoid the traditional middle linebacker prospects and find players with transitional skills to play one of the two inside linebacker spots.

Most of all, however, the Packers are going to take it slow.