San Francisco 49ers

49ers’ defensive goal in 2015: Confuse the offense

The 49ers led the NFL in interceptions last year. Safety Antoine Bethea (41) said the goal this season was to keep opposing offenses on their heels with plenty of pre-snap movement.
The 49ers led the NFL in interceptions last year. Safety Antoine Bethea (41) said the goal this season was to keep opposing offenses on their heels with plenty of pre-snap movement. The Sacramento Bee

Changes to the 49ers’ defense will go beyond the losses of fixtures like Justin Smith and Patrick Willis.

The team will continue to feature a base 3-4 alignment under new coordinator Eric Mangini. But players are learning a new lexicon this offseason and are moving around before the snap in an effort to confuse the opposing offense.

“All D-coordinators have their style,” said safety Antoine Bethea. “Coach Mangini, his thing is that we’re going to cause confusion. The offense is not going to know what we’re going to do each down. That could be bringing pressure; that could be dropping eight (players) in coverage. But it’s keeping the offense on their heels.”

The 49ers have not made any of their assistant coaches, including Mangini, available for interviews since they were hired in January. Still, it seems the former head coach of the Jets and Browns is maintaining his reputation for fielding a complex – and aggressive – scheme.

That would be a departure from the team’s defenses in recent years, which finished in the top five annually in yards allowed and which may have been most notable for their simplicity.

Under coordinator Vic Fangio, the 49ers mostly relied on their front four defenders to pressure the quarterback and seldom blitzed. As a result, the 49ers finished in the top 10 in sacks only once in the last four seasons – in 2011, when they finished with 42.

But having a full complement of players in coverage also cut down on big offensive plays and led to plenty of turnovers. San Francisco tied for the league lead in takeaways in 2011 and had more interceptions, 23, than any other defense last season.

The 49ers may end up blitzing more under Mangini.

When asked if this year’s defense will be more aggressive than previous versions, defensive end Tony Jerod-Eddie said, “I would say so. There’s a lot of moving around, a lot more ‘We’re going to get ’em.’

“Then again, we’re putting everything in right now, so we can all learn it and put it on film. So I don’t know. I’ve never been in a game with Mangini, so we’ll see.”

Like Jerod-Eddie, head coach Jim Tomsula noted that the team is installing the playbook now and that the actual schemes and strategies used in September will be honed throughout the offseason, training camp and preseason.

“You’ve seen that everywhere you go,” he said. “(During) OTAs, you put things in – you’ve got that time to put things in and kind of see what guys do better, so there’s a lot of that going on.”

Something else the coaches must determine: which players will be on the field.

During Thursday’s no-pads, no-contact practice, Jerod-Eddie played left defensive end with the first-team unit while Ian Williams lined up at nose tackle and Quinton Dial was at right defensive end, where Smith started the last seven seasons.

But three other players likely to factor in heavily during the regular season were not on hand. Darnell Dockett is still rehabilitating from last summer’s ACL tear. Glenn Dorsey worked out on a side field with an undisclosed injury. Arik Armstead, the 49ers’ first-round pick from Oregon and Pleasant Grove High School, won’t be able to join practice until early next month.

Meanwhile, Tank Carradine, an early second-round pick in 2013, likely will figure in as a passing-down specialist from the right side. That list of names, Carradine said, shows how strong the defensive line can be even without a mainstay like Smith.

“We’ve got a great group of defensive ends,” he said. “We’re all going to work together and get the job done. I’m excited about it.”

Matt Barrows: @mattbarrows, read more about the team at