MANKATO, Minn. -- There's little question the feel-good story of Minnesota Vikings training camp has been Adam Thielen, the 23-year-old receiver from Detroit Lakes, Minnesota, who is back on the grounds of his old college campus trying to make the team after a year on the Vikings' practice squad.

Thielen had a solid training camp in 2013, but he has earned praise from general manager Rick Spielman and coach Mike Zimmer this year about being one of the most improved players on the Vikings' roster.

That recognition started during the Vikings' offseason program, and after an impressive preseason debut that included 68 all-purpose yards and a tackle for a 4-yard loss in punt coverage, Thielen seems like a strong bet to make the Vikings' 53-man roster. And yet -- in true Minnesota fashion -- he won't assume anything.

"I'll be trying to give him a compliment, and he still feels like he's not part of the team," said wide receiver Cordarrelle Patterson, who has developed a friendship with Thielen since they started rooming together at training camp last year. "I tell him every day, 'You're part of the team.'"

Said Thielen: 'I think he's just playing with you guys. He's a good dude, but I'm trying not to think about it. He's my good buddy, so of course he's going to say that."

Patterson could be proven right in a few weeks, if Thielen keeps up the work he has done so far. He has worked well with rookie quarterback Teddy Bridgewater since the Vikings' rookie camp in May, and Thielen stepped in for injured punt returner Marcus Sherels in the Vikings' preseason opener, nearly breaking his second return for a touchdown.

"You can win a lot of football games with guys like him," Zimmer said.

Patterson does have one complaint about Thielen, though.

"He goes to sleep too early," Patterson said. "I'll kind of want to stay up and talk about things, talk about life, but he's already asleep."

Perhaps the receivers will be able to continue their friendship on Vikings road trips this year.

"I had defensive guys, veterans, saying Adam should have been a part of this team last year. I feel like that, too," Patterson said.. "He feels like he's got a lot to prove to try to make himself. But he's a part of this team, I don't see any way he could not be a part of this team."