Ball in the family
	Trace the spread of the West Coast offense from its roots with Bill Walsh and his mentors to its latest proponents, some of whom might barely even know the man. Launch

Defending the original West Coast offense was hard enough. Defending what the West Coast offense has become has turned into quite a headache for defensive coordinators.

Too many hybrids have developed. Bucs coach Jon Gruden produced a complex running attack out of the I-formation. Eagles coach Andy Reid anchored a power running attack around a physical offensive line. There are shotgun formations that didn't exist in the early days. The mobile quarterback has created a different set of problems. Formations from the four-receiver run-and-shoot have been incorporated.

The West Coast offense has gone global, and defenses have been forced to expand their playbooks to stop it.

"You have to create special packages now to stop the run," Titans coach Jeff Fisher said. "It keeps making you mix a balance of defenses to go at their strong side. You have to do something unless you have great cornerbacks. The West Coast offense just keeps evolving."

	“	Pressure. You have to get pressure. At first, teams didn't do that all the time. ”
		— Saints coach Jim Haslett

Answers to the West Coast offense are varied, but they come down to one simple but tough principle.

"Pressure," Saints coach Jim Haslett said. "You have to get pressure. At first, teams didn't do that all the time. The West Coast offense adapts. The principle that Bill Walsh used was throwing quick and getting the football out quickly. Coaches use so many formations. Teams go empty in the backfield. They go into shotgun. They use two and three tight ends."

But defenses adapt, too. The simple zone pass coverage approach was too simple, because it didn't supply the pressure. Dropping seven defenders directly into coverages left only four to rush the passer. Walsh countered with smaller, quicker offensive lines to block at the legs of the pass rushers while his quarterbacks threw timing routes. That combination allowed Joe Montana -- and most good quarterbacks in this system -- to destroy simple zone approaches.

So everybody tried blitzing. Smart quarterbacks took those aggressive schemes apart.

	Bengals coach Dick LeBeau was one of the first coaches to figure out how to slow down the West Coast offense.

While complexity worked for Walsh, defenses had to come up with their own complex answers. Credit current Bengals coach Dick LeBeau for doing that with the zone-blitz scheme he developed as a Steelers defensive assistant from 1992-96. Offering the best of both worlds, the zone blitz allowed defenses to apply pressure by sending a fifth or sixth defender at the quarterback but still defend the secondary by using safer zone coverages than more traditional schemes. The key was getting a defensive lineman to drop into a short zone.

"There is a normal evolution of a defense, and with those defenses, you have to have checks and balances," LeBeau said. "The West Coast offense is here to stay, and so is the Fire Zone. It's an attack defense. It allows you to get some good pressure on a passing game."

In many ways, the 3-4 schemes that LeBeau and others worked in a decade or two ago were perfect breeding grounds for zone blitzes. Having four linebackers added a certain degree of unpredictability, because offensive lines didn't know which linebacker would be attacking the quarterback. Second, teams lining up in a 3-4 formation usually employed bigger, more physical cornerbacks. Often, they played off the line of scrimmage.

In the Fire Zone, LeBeau sent different people at the quarterback on any given down. He blitzed cornerbacks. He blitzed safeties. He blitzed middle linebackers. The more he experimented, the more options he found to drive quarterbacks crazy. Unlike the defenses that Walsh had faced previously, LeBeau's zone blitz approach created the pressure but didn't have the breakdowns in coverage, because defenders tried to keep plays in front of them.

"You try to apply the pressure to the blocking area that the opponent is weak and try to get to the quarterback with that extra guy," LeBeau said.

After a few years, the hybrid offensive models developed from the personalities of the head coaches who learned the system from Walsh. Many of the old disciplines were tossed aside. Walsh, for instance, didn't like adding a fourth receiver, because he loved having a tight end on the field. And Walsh didn't use the shotgun, because Montana didn't like it.

Now, anything goes.

"Now, you are seeing more spread formations and quicker throws," LeBeau said. "You're seeing five-receiver sets. You're seeing one running back and four receivers."

So the more that the offenses spread the field, the more defenses can try to overload one side of a blocking scheme and sneak in a blitzing defense. To throw five receivers into a route means having only five blockers to protect the quarterback.

From LeBeau's zone blitzing concept, defenses are trying to get one or two extra defenders on one side of the blocking scheme. That extra unblocked defender forces the quarterback to go to his checkdown receiver or face the possiblity of getting sacked.

"Now, there is more five-man pressure against the West Coast offense, because the formations are more spread," said Foge Fazio, Cleveland Browns defensive coordinator. "You take the zone blitz and get those five-man pressures going. You have to make sure that when you do that, you clog the throwing lanes. You get some man coverages underneath. You can get some double coverages in there against the team's best receiver."

The key is making sure the quarterback doesn't have time.

	“	Listen, we had to come up with something. The zone blitz was designed because defenses have to find a safe way to pressure against offenses that had more than 40 throws a game. You can't let a team throw the ball 40 times a game without getting pressure on the quarterback. ”
		— Bengals coach Dick Lebeau

"Defense is a matter of counterpunching," LeBeau said. "A defensive coordinator can only react to what an offensive guy is going to do. Listen, we had to come up with something. The zone blitz was designed because defenses have to find a safe way to pressure against offenses that had more than 40 throws a game. You can't let a team throw the ball 40 times a game without getting pressure on the quarterback."

Some defensive coaches believe the best thing to do is go overboard in applying the pressure. Attack. Attack. Attack. The more a quarterback is attacked, the more chances he is going to be hit. A battered quarterback is an inaccurate quarterback.

Unfortunately, a lot of teams don't have the cornerbacks who can handle the type of man coverage required to allow a sixth or seventh defender to make quick rushes. Zones might be the ultimate answer to the West Coast offense, but man coverage gives the cornerback the best chance to knock a receiver's timing off with a chuck at the line of scrimmage.

Nevertheless, the trend toward aggressive, attacking defenses led to more quarterbacks lining up in the shotgun formation.

"The shotgun gives the quarterback a split second extra to see the defenses," LeBeau said. "I know Joe Montana didn't use it, but Joe didn't like the shotgun."

Whatever their approach, defensive coordinators have been forced to keep the playbook simple enough that players can learn it quickly. Free agency and the salary cap are causing roster turnovers of 25 to 50 percent a year. If the scheme is so tough that new, young players can't learn it, it must be changed.

Tony Dungy's "Cover 2" approach is the best base defense in the salary-cap era, because it limits the big plays by using zone principles while giving Dungy the opportunity to work in his zone blitzes.

But even "Cover 2" coaches are having their troubles against West Coast offenses this year. With offenses spreading the field with receivers, defenses are forced to spread out to cover them. That makes the blitzing defender run a little farther to get to the quarterback.

Spreading the field also creates more space in the middle, and the influx of great tight ends are giving quarterbacks the perfect weapon -- big targets where the holes in the zone might be found.

As always, defenses will find a way to counterpunch, and the chess match will continue.

John Clayton is a senior writer for ESPN.com.