MANKATO — The demise of the third linebacker in Minnesota’s defense, and that of every other NFL team in a 4-3 scheme, has not been exaggerated.

With the nickel package now in majority control of the playbook, thanks to the prevalence of passing attacks dominating the league these days, the third cornerback is more of a starter. The base defense might only be employed 30 or 40 percent of the time.

That doesn’t mean the weak side linebacker for the Vikings has gone the way of the leather helmet, though. The retirement of 11-year veteran Chad Greenway created an opening in the lineup that Ben Gedeon, Emmanuel Lamur and Edmond Robison are in a spirited competition to fill.

“A lot of teams are still going to keep you in base, and we need a guy who can cover tight ends, a guy who can fit up the run and be good in the zone coverages,” linebackers coach Adam Zimmer said. “So it’s an important position, and it’s not one that we’re going to overlook.”

The absence of Greenway and his boisterous leadership has been impossible to ignore, too. For the first time since Zimmer was hired along with his father, the position coach actually has seniority in the meeting room. Greenway is one year older than the younger Zimmer.

“He was the main guy in the locker room, and he kept everybody together,” Robinson said. “It’s a little weird not having him around, but I’m happy for him that he’s had a great career and retired. Everything’s still the same. We’re just missing Chad a little bit.”

With Anthony Barr (strong side) and Eric Kendricks (middle) at the other two linebacker spots, the Vikings are young and fast. So it’s an easy decision to replace the weak side linebacker with a nickel cornerback in obvious passing situations with three or more wide receivers. Greenway’s replacement isn’t as obvious, though he only played 39 percent of the snaps last season.

Lamur has the most experience, entering his sixth season in the league. The first two years were under coach Mike Zimmer in Cincinnati. He’s 6-foot-4 and 245 pounds, with an edge in quickness and agility.

Robinson was a seventh-round draft pick in 2015 out of Newberry, an NCAA Division II school. He’s 6-3 and 245 pounds, still coming into his own as far as NFL instincts with an ability to hit hard and run well for his size.

Gedeon is a fourth-round draft pick who mostly played middle linebacker at Michigan but has been one of the early rookie standouts in training camp, with often unprompted praise coming from the coaches in interview sessions with the media. He’s 6-2 and 245 pounds, with an old-school, stuff-the-run style.

“He’s smart,” Zimmer said. “You tell him one time, and he gets it pretty good.”

The weak side spot requires plenty of athleticism and instinct, with a keen understanding of blocking schemes, and it allows for more freedom. Zimmer went so far as to declare it easier than the strong side.

“These first few days, I was struggling a little bit, learning the schemes,” Gedeon said, “but as practices have been going on I’ve been kind of picking up on things faster and being able to react faster.”

Open competitions for the starting lineup have been rare since Zimmer arrived, with another multiple-player audition ongoing at defensive tackle this year.

“I’m definitely embracing the role right now,” Lamur said. “I just want to show my team, the organization, that I’m the man for the spot.”