Adam Thielen stood there, not sure what was going on at first. But he had an idea. After all, he’s the prototypical NFL overachiever. He’s used to having his book judged by its cover.

It was Aug. 10 and the Vikings were in Cincinnati. Two days of joint practices with the Bengals had just begun, and it was time for 1-on-1 drills between receivers and defensive backs. Thielen, a Vikings receiver, was among the first to line up. But the Bengals’ starting cornerbacks, Dre Kirkpatrick and Adam “Pacman” Jones, wanted no part of him.

Afraid? No. Condescending? A little bit.

The two cornerbacks, onlookers reported, teased Thielen and fellow receiver Isaac Fruechte, saying, “We want to go against some dawgs! This team has no dawgs!” Thielen said he couldn’t hear what they were saying but realized what was happening when Kirkpatrick and Jones dropped back in line so they could face other receivers.

“They wouldn’t go against me, so they made the backups come up,” Thielen said. “It’s disrespectful. You feel disrespected, but at the same time, it is what it is. I really don’t care.”

Fellow Vikings receiver Cordarrelle Patterson is Thielen’s best friend on the team. He has seen his buddy prejudged before. But Patterson is not complaining, since he believes it’s to the Vikings’ advantage.

“We want people to look at Adam and say, ‘Oh, he’s nothing. He’s just a short white guy. He can’t play no ball,’ ” Patterson said. “And then he gets open. It seems like every play, he’s open. And on special teams, he’s doing everything. Blocking punts for touchdowns, running reverses or whatever. It seems like he’s always the right guy at the right spot at the right time.”

Actually, Thielen isn’t short. He’s 6-2. He also weighs 200 pounds and ran a 4.45 in the 40-yard dash at the NFL’s 2013 super regional combine. Meanwhile, the 6-3, 210-pound Fruechte, who also is white, might be the fastest receiver on the 90-man roster.

But stereotypes do exist, according to players and coaches. Thielen isn’t insulted by comparisons to other players such as Wes Welker. He would love to match Welker’s career. But they’re completely different types of players, Vikings coach George Stewart points out.

“Wes was a small slot guy; Adam is 6-2 and fast,” Stewart said. “Adam is an outside guy who can play inside, too. If anything, I see the correlation being an Isaac Bruce. I think that’s the problem that Adam has had. He gets lumped in with people. He’s his own man, and he’s a pro’s pro.”

Thielen was born in northern Minnesota. He went to Detroit Lakes High School, where he stood out in football, basketball, baseball and golf. He won a state team title in golf and is considered the best golfer on the Vikings.

As a senior, he was all-state on a 9-1 football team. He ended up at Division II Minnesota State Mankato, but he’s not complaining. That’s where he met his wife, Caitlin, a standout soccer player and the mother of the couple’s first child, a boy, due in October.

As for the NFL, talent and dedication always find a pathway onto a 53-man roster. After spending 2013 on the Vikings practice squad as an undrafted free agent, Thielen has taken on a larger role every season since. Already a special teams leader, he has been a steady presence in the Vikings’ three-man receiver sets this summer.

Thielen, 25, has moved ahead of sneaky playmaker Jarius Wright on the Vikings’ unofficial depth chart. Wright, of course, has missed the first two preseason games because of a leg injury. But Thielen also is showing more versatility.

Some defenders might be caught off-guard when they first encounter Thielen. Wright told the story of the 2014 season finale when the Bears sideline was yelling “Decoy!” when Thielen ran onto the field for a few snaps later in the game.

Asked if he thought race was a factor in some of the comments, Thielen said he hadn’t really thought about it and added, “I don’t know if it’s a white thing or what. I can’t really worry about that because I don’t really care what people think about me or the color of my skin. I’m just playing football.

“In that Chicago game, their coaches and players were yelling, ‘Decoy. He’s only a blocking receiver.’ It was kind of funny.”

Then the blocking receiver ran past the secondary and caught a 44-yard touchdown pass from Teddy Bridgewater in a 13-9 win.

Two days after that Aug. 10 practice in Cincinnati, the Vikings beat the Bengals in a preseason opener. The first touchdown of the game was set up by Thielen making a leaping catch in traffic over the middle for 22 yards. Coach Mike Zimmer said the throw exemplifies Bridgewater’s newfound willingness to trust a receiver to make a contested play down the field.

In Thursday’s second preseason game, an 18-11 victory at Seattle, Thielen led Vikings receivers with four catches for 61 yards. He caught an 18-yarder over the middle from Shaun Hill on third-and-8 on the Vikings’ first drive of the game, and a 17-yarder from Joel Stave on third-and-10 to set up a 27-yard field goal in the closing seconds of the first half.

“Adam always kind of plays with a chip on his shoulder,” Zimmer said. “I know he got into a little altercation [with Jones] down there [in Cincinnati]. But that’s how he is and that’s how he has to play.”

Yes, Jones eventually did have to cover Thielen back on Aug. 10. When he did, he ripped Thielen’s helmet off. He wasn’t happy. Teammates stepped in.

Thielen said the altercation had nothing to do with Jones’ initial reaction to him during the 1-on-1 drills.

“No, not at all,” Thielen said. “When he first saw me, we hadn’t done anything yet, so he and [Kirkpatrick] probably didn’t know anything about me. But once we started practicing, I feel like they realized pretty quick that I could play.”

And if they didn’t, Patterson doesn’t care.

“Adam is as good as any receiver on our team,” Patterson said. “I saw they didn’t want to go against him. That’s just something they wanted to do. But I’d match Adam up with those two guys any day. I don’t care how they feel. That’s how we feel.”