Did you know that Adam Thielen was undrafted?

Kidding, of course. While the storyline on Thielen may seem repetitive for Vikings fans who've been rooting for the Minnesota product since he earned a shot on a tryout basis in 2013.

But no matter how many times you've heard this one, it doesn't stop being impressive. Since spending his rookie campaign on Minnesota's practice squad, Thielen has since risen to be one of the NFL's top receivers.

NFL.com's Shaun O'Hara recently rolled out the league’s top 10 undrafted players heading into the 2021 campaign, and he ranked Thielen No. 4 overall. O'Hara wrote:

Thielen has become a huge receiving threat for the Vikings since his 2016 breakout campaign. He's coming off a 14-TD performance and could serve as Kirk Cousins' favorite red-zone target again this year thanks to his route-running skills and elite hands. Thielen should benefit from lining up opposite Offensive Rookie of the Year runner-up Justin Jefferson, who avoided a major injury in training camp last week, as a routine chain-mover in this explosive offense.

Another name on O'Hara's list will ring familiar for Vikings fans: Eagles safety Anthony Harris.

Harris spent the first six seasons of his NFL career in Minnesota after signing as an undrafted rookie in 2015. He joined Philadelphia this spring as a free agent.

O'Hara ranked Harris ninth on his list.

After leading the league in INTs in 2019, Harris had a letdown season in Minnesota while playing on the franchise tag in 2020. He signed a one-year, prove-it deal with the Eagles this offseason. The success of the Philadelphia defense will depend on its health, something the team hasn't been able to sustain since its Super Bowl run. If the Eagles can keep their defensive stars on the field, Harris is primed to have a bounce-back year as he reunites with Eagles DC Jonathan Gannon, who was the Vikings assistant defensive backs coach during Harris' first three seasons.

And topping the rankings ahead of Thielen? O'Hara listed Bucs linebacker Shaquil Barrett at No. 1, Chargers running back Austin Ekeler at No. 2 and Ravens longtime kicker Justin Tucker at No. 3.

The Vikings are scheduled to see Tucker and Ekeler in back-to-back road games in Weeks 9 and 10. O'Hara noted the following of Ekeler:

Everybody talks about Justin Herbert and his tremendous rookie season, and rightfully so, but Ekeler has been outstanding since taking over the full-time role in the backfield. While he's proven to be reliable on first and second down, his biggest strength is as a receiver out of the backfield – an asset new Chargers [Offensive Coordinator] Joe Lombardi will love to use in his system.

Graff's training camp takeaways include strides by Osborn, DL improvement

We're now less than a week away from the Vikings first preseason game of the 2021 season.

Minnesota will host Denver at U.S. Bank Stadium Saturday afternoon, and tickets are available here.

Before that, though, the Vikings and Broncos will participate in joint practices Wednesday and Thursday to wrap up this year's training camp. In anticipation, Chad Graff of The Athletic shared his 11 takeaways from camp thus far, leading the list with second-year receiver K.J. Osborn. Graff wrote:

Dede Westbrook was probably the odds-on favorite for this spot at the start of training camp, but Westbrook hasn't yet been a full participant at any practice due to his continued rehab from a torn ACL last season.

In the meantime, Osborn has stood out nearly every practice, routinely making impressive catches. His playing time has increased, especially after Justin Jefferson suffered [an injury last week], and Osborn has continued making plays even in his opportunities with the first-team offense. At this point, it seems hard to imagine Osborn falling down the depth chart even if Westbrook is back and fully healthy by Week 1.

Graff also noted pros and cons for rookie Ihmir Smith-Marsette in the receivers room.

Good news/bad news for the rookie from Iowa. On the one hand, he's been a lot better as a wide receiver than I expected, and with Westbrook out, he has probably a pretty clear shot to be the team's No. 4 option there. On the other hand, the Vikings don't use more than two wide receivers very often, so Zimmer stresses that the depth players there need to be very good at special teams — and Smith-Marsette hasn't been great there so far.

While the Vikings drafted Smith-Marsette in the fifth round in part because of his prowess as a returner, he hasn't stood out there and Zimmer clearly isn't happy with his performance on special teams.

Graff quoted Vikings Head Coach Mike Zimmer, who said Monday that Smith-Marsette has "a lot of work to do" on special teams.

Graff said that while the linebacker depth "is lacking" for Minnesota, the defensive line has "improved drastically" from its rough state in 2020.

I'd argue that the Vikings had the worst interior defensive line in the league a year ago, but that's far from the case now. When Sheldon Richardson is your backup, you've got a strong setup in the middle. We've only seen a limited amount of Michael Pierce since he missed the start of training camp due to a calf injury, but he's been super impressive. His size and strength are eye-popping even among the biggest guys on the field, and Zimmer noted that it could potentially help center Garrett Bradbury since he has to frequently face Pierce.

Dalvin Tomlinson looks as advertised, too, and the depth behind them could leave the Vikings with some tough decisions. Armon Watts seems to have gotten better in the offseason, and Zimmer shouted out James Lynch as someone who has done well in camp. That combination on the interior of the defensive line is so much better than this time one year ago.

To see all 11 of Graff's takeaways, click here.