The competition is wide open for the Vikings' backup wide receiver positions

Kirk Cousins arrived in Minnesota knowing two things about his receiver corps: Adam Thielen and Stefon Diggs are stars in the making, if not already, and the rest of the depth chart consists of wide-open lanes for unproven targets.

That's how the Vikings' most intriguing roster battle remains midway through training camp, where Laquon Treadwell, Kendall Wright, Stacy Coley, Brandon Zylstra, Tarvarres King, Cayleb Jones and others are stating cases for receiver spots three, four, five and possibly six.

Only one of them is a lock: Treadwell, the maligned former first-round pick entering his third NFL season with 21 career catches. He's taken nearly every snap this offseason as the third receiver. He keeps catching passes, too.

"I just go where my reads take me, and he keeps getting the football," Cousins said. "He's had a great camp. The goal is not to just have a great camp but turn it into an outstanding season. So, we've got to make sure he keeps doing what he's been doing all the way through this fall."

Before taking a snap with the Vikings, Cousins knew only of Treadwell's slim statistics. They included just 35 targets last year on Case Keenum's 481 passes.

"You just had seen the numbers, or lack of production in the first couple of seasons," Cousins said. "But I get out here and see a guy who comes to work every day; knows the plays; knows the system; has a good sense of the game; makes aggressive, tough catches; and has run a variety of routes and really shown up on all of them."

Treadwell, 23, has a reputation around Vikings headquarters for working hard, but not necessarily smart. He claims to have grown in his understanding there.

Behind Treadwell, the Vikings are looking for their young receivers to stand out on special teams. That's how non-contributors on offense get playing time. Coach Mike Zimmer appeared in a special teams meeting this spring to tell younger players just that — play the third phases or not at all.

Coverage and return units are how Jones, a third-year receiver, plans to get his foot in the door.

"My emphasis needs to be more important on special teams," said Jones, who is suspended four games for a PED violation. "Adam is a prime example of playing special teams, making his way on the field, and he hasn't looked back. That's the path I'm choosing to take."

It's a hurdle veteran receiver Kendall Wright will have to overcome, otherwise he "probably won't dress on game day," Zimmer said. Wright, a 2012 first-round pick by the Titans, has played a total of four snaps on special teams in his career. He's taken a handful of first-team reps but has primarily spent camp catching passes from backup quarterback Trevor Siemian.

Wright is looking forward to Saturday's preseason opener in Denver, where the experienced slot receiver wants to separate himself from the others.

One of the camp standouts so far has been Zylstra, the former local star from New London-Spicer and Concordia (Moorhead) College. He's big enough (6-2, 215 pounds) to hold special teams roles typically reserved for bigger players at linebacker or safety, according to special teams coordinator Mike Priefer.

The Vikings have Zylstra, who led the Canadian Football League with 1,697 yards last season, on nearly every special teams unit. He's even worked as a backup holder on extra-point attempts after practice.

"I'm going to do what I can to the best of my ability," Zylstra said, "and see how it pans out from there."