After falling behind the Steelers in the fourth quarter last Sunday, the Seahawks turned to one of their offensive staples to kick-start their comeback.

Before the first play of the drive, Seahawks quarterback Russell Wilson lined up in the shotgun with rookie running back Thomas Rawls, who has been beastly in his own right while filling in for the injured Marshawn Lynch, standing to his left.

As Wilson caught the shotgun snap, Steelers outside linebacker James Harrison was allowed to bowl into the backfield. Unblocked, Harrison made a beeline for Rawls, who crossed in front of Wilson with his hands extended to take the handoff. Instead, Wilson kept the ball, stepped around the helpless Harrison and sprinted for a first down.

The Seahawks soon pulled ahead with a touchdown and then scored another to win a 39-30 shootout with the Steelers. But they won the game with right arm of Wilson, who threw five touchdown passes, instead of his legs. After that 10-yard run, Seahawks offensive coordinator Darrell Bevell called only two more of those read-option runs, with Rawls twice taking the handoff for modest gains.

“[The read option] is not the only thing we do,” Wilson said on a Wednesday conference call.

The Seahawks, whom the Vikings will host Sunday at TCF Bank Stadium, were one of a few teams that started the NFL’s read-option revolution in 2012, leaving unprepared defenses scrambling for answers all season long. The tactic, also known as the zone read, helped the Seahawks get to the past two Super Bowls, winning one of them.

They have used the read option significantly less this season as NFL defenses have devised schemes to slow dual-threats such as Wilson. But Wilson’s keeper against the Steelers showed that it still is a significant part of Seattle’s offense, something the Vikings will be preparing for all week.

College tactic comes to NFL

In 2012, the Seahawks, Redskins and 49ers caught defenses off guard with read-option runs and the deceptive play-action passes that complement them on their way to the playoffs. The 49ers, powered by the lanky legs of quarterback Colin Kaepernick, came 5 yards short of winning the Super Bowl.

“This thing just showed up,” said Andy Benoit, a writer for Sports Illustrated and who specializes in NFL schematics. “[NFL] coaches knew about it. They were aware of it. But no one had practiced it. People believed it was a college tactic. But then pro teams started running it with guys who were really good at running it.

“The quarterback became a threat in the running game, and there were no principles to account for that. Schemes were not designed for the quarterback. The defense always had one more defender in the box than what that the offense had. But when the quarterback became a running option, the numbers got leveled out.”

At the start of read-option plays, the quarterback lines up in the shotgun or pistol formation with a running back close by. After the snap, the offense leaves one edge defender, often a defensive end, unblocked. The quarterback reads that defender’s path then decides whether to keep the ball or hand it to the back. If the QB makes the right read, the isolated defender is in a no-win position.

“The scheme was working with those defensive ends because it created a conflict of assignment,” Benoit said.

Benoit said the biggest key was not leaving one defender alone to deal with both the quarterback and the running back at the mesh point of the could-be handoff. Teams now often assign multiple defenders to the quarterback and running back and their specific objectives on any given play can vary.

Defenses strike back

After the shock and awe of 2012, defensive coaches met with their college counterparts and huddled with their NFL peers to come up with schemes to combat the read option. The yards-per-carry average on read-option runs has declined every season since.

“I do think there are a lot of good coaches in the NFL and each new thing that comes out, whether it be the Wildcat or the unbalanced line a few years ago or the zone read now or double-A-gap blitzes, guys figure a lot of stuff out,” Vikings coach Mike Zimmer said. “That’s why you’ve always got to stay on top of things and keep trying to invent.”

But even though read-options runs have become less effective, their use continues to rise, according to Pro Football Focus. During that pioneering 2012 season, NFL teams ran the ball on read-option plays 532 times and averaged 6.0 yards per carry. This season, teams are on pace to use 1,825 read-option runs but are gaining only 4.5 yards per carry.

The most successful team has been the Carolina Panthers, another of the read-option innovators from 2012. They have expanded that diverse option attack built around MVP candidate Cam Newton, who has rushed for seven scores, and are undefeated as they race toward a third consecutive NFC South title.

The Seahawks also remain one of the NFL’s biggest users of read-option plays, along with the Panthers, Philadelphia Eagles, Buffalo Bills and Miami Dolphins. However, they have scaled down the frequency significantly.

Last season, Wilson and his running backs gained 1,395 yards and four touchdowns on 249 read-option runs, according to Pro Football Focus. This season, they are on pace for 723 yards and three touchdowns on 143.

“I don’t think there is any strategic planning behind it,” Wilson said. “We have so many different things that we can do at a high level, especially when we’re clicking.”

One also can presume that Wilson getting an $88 million megadeal in the offseason means that the Seahawks want to keep him out of harm’s way so he doesn’t become damaged goods like Robert Griffin III, the poster child of the 2012 read-option revolution.

But Seattle’s victory over Pittsburgh was proof that the Seahawks still will rely on the read option in key spots. So the Vikings must be ready for it.

“They’re going to make plays with it,” defensive end Brian Robison said. “But you have to do the best job you can do in order to be at the right place at the right time.”