Depending on the down and distance, the Vikings defensive line changes like a shapeshifter.

The strength of a budding defense, eight linemen can become the teeth of head coach Mike Zimmer's system. Brian Robison, Sharrif Floyd, Linval Joseph and Everson Griffen start and a constant rotation follows.

In obvious passing situations, Danielle Hunter and Tom Johnson enter with Robison shifting to the interior. That combination of Hunter, Johnson, Robison and Griffen netted 27 sacks last season.

And they're jelling like never before, said defensive line coach Andre Patterson.

"The four of them can communicate without words even being said," Patterson said during training camp. "So I get to points in games where I just let B-Rob call it. B-Rob calls it, whether we run a game or whether we go straight, because they trust him and they can communicate with each other without giving signals."

They follow the example of Griffen, like Robison one of four player-voted team captains. He made his first Pro Bowl last year with 10 ½ sacks despite playing through a shoulder injury that required a brace during the second half of the season.

Opponents double- and, sometimes, triple-teamed Griffen, though his growing supporting cast will make that tougher in 2016.

Hunter's six sacks last season ranked second among NFL rookies. Robison has sacrificed stats for new roles, leading the pass-rush line from the interior, where he's either over center or lined up with a guard. And Johnson, the 31-year-old pass rush specialist, has had his load lightened with the return of Shamar Stephen.

Stephen, a 2014 seventh-round pick, missed most of last season because of turf toe and could be a key player against the run.

"We missed him a bunch last year," Zimmer said. "He's big. He's strong at the point of attack."

The line's biggest questions are the health of Floyd and Joseph after the duo missed a combined eight starts. Floyd continued to deal with a knee injury this preseason but is expected to play Sunday in Tennessee.

"He has had an injury history," Zimmer said. "But if you're healthy, you go. He's not on any pitch count."

Joseph, the anchor at nose tackle, was having a strong season before suffering his own case of turf toe, which required January surgery.

Injuries are likely again, but the line's quality of depth should help it get through the bumps and bruises of an NFL season.