Aaaaand …. here we go! In many ways, the Vikings' 2013 season officially gets underway Friday – first training camp walkthrough at 10:30 a.m., first practice at 2:30 p.m. in Mankato. And yes we know a lot can and will happen between now and Sept. 8, the day the Vikings open the regular season at Detroit. But taking the 90 players currently on the roster, we're delivering our in-depth position-by-position report as a primer for the opening of camp.

RECEIVERS

Currently on roster: 12

Likely to make opening day roster: 6

Certain to make the team: Greg Jennings, Cordarrelle Patterson, Jarius Wright, Jerome Simpson

On the bubble: Joe Webb, Stephen Burton, Chris Summers

Practice squad candidates: Greg Childs, Rod Smith, Adam Thielen

Camp depth: Erik Highsmith, LaMark Brown

Biggest offseason developments: Unquestionably, the organization's biggest move of the entire offseason was the March 11 trade of Percy Harvin to Seattle, a deal from which General Manager Rick Spielman procured three draft picks – first- and seventh-rounders for this year and a fourth-rounder in 2014. … Four days after the Harvin trade, Spielman signed veteran Greg Jennings to a five-year contract, worth up to $47.5 million. … In April, the Vikings selected Cordarrelle Patterson with the 29th pick, a selection they acquired from New England in exchange for four other picks.

What we'll be watching: Jennings and Patterson. Patterson and Jennings.

Is the 29-year-old veteran ready to become Christian Ponder's go-to guy? Is the explosive yet raw rookie making strides in absorbing the offense and fine-tuning his route running?

If the Vikings passing attack is to make significant improvement in 2013, Jennings and Patterson will each have to make good on the realistic expectations set out for them. Through camp, it will be interesting to see how each player fares individually while also keeping an eye on their interaction with one another with Jennings tasked with mentoring Patterson.

Without question, we also want to see how Webb is handling his transition to a new position. His athleticism is off the charts. His hands appear to be solid. Now comes the question on whether he can process the offense from a new position, learning to get in rhythm with Christian Ponder and establishing consistency in his route running.

On a deep sleeper note, we're intrigued to keep an eye on Thielen, a native of Detroit Lakes who played his college ball in Mankato. Thielen will have to carve out a role on special teams (perhaps as a punt returner?) if he has any hopes of making the team. But over the summer, he flashed signs of promise and is interesting as a developmental guy.

Star Tribune offseason excerpt:

To feel fully comfortable with his move, Jennings made sure to review film. He threw the Vikings' tape on, he said, not so much to analyze intricacies in coordinator Bill Musgrave's offense but rather to zero in exclusively on Ponder.

"I had to see what I was getting myself into," Jennings admitted.

He had, after all, spent his first seven seasons catching passes from Brett Favre and Aaron Rodgers.

In Ponder, Jennings said, he saw an athletic young quarterback with great potential – if only he had more help.

In the Vikings, Jennings sees a team on the rise.

"You want to go to a team that's still a contender, that has an opportunity to win but the window isn't closing. The window is opening up. And I saw that with this ball club last year. They kind of snuck up on everybody."

– March 16

TIGHT ENDS

Currently on roster: 5

Likely to make opening day roster: 3

Certain to make the team: Kyle Rudolph, John Carlson, Rhett Ellison

On the bubble: Chase Ford

Camp depth: Colin Anderson

Biggest offseason developments: Rudolph received a last-minute invite to the Pro Bowl after Atlanta's Tony Gonzalez opted out. Rudolph capitalized by winning the game's MVP honors, catching five balls for 122 yards, including a 3-yard TD from Eli Manning. … Carlson restructured the five-year, $25 million deal he signed in March 2012, reducing his base salary for 2013.

What we'll be watching: Coach Leslie Frazier believes Rudolph returned from his Pro Bowl trip in a different state of mind – more confident, more comfortable and eager to show that he is indeed one of the league's elite pass-catching tight ends with improved blocking ability to boot. Getting a measure for just how much better Rudolph has become will be a priority.

We'll also keep a close watch on Carlson, a free-agent bust in 2012, who finished his first season with the Vikings with only eight catches for 43 yards. Carlson suffered a knee injury early in training camp last summer. And whether that setback was the biggest reason for his dismal year is up for debate. What's clear is that the Vikings need him to be much more productive this season.

Star Tribune offseason excerpt:

Rudolph said he used his time in Hawaii to work closely with Dallas standout Jason Witten, an elite pass catcher who also takes pride in his blocking. Rounding out that part of his skill set will be key for Rudolph. But Frazier's excitement is obvious with his gushing praise Wednesday for Rudolph's detailed route running, focused practice efforts and control in meetings.

"It's obvious he has taken his game up another notch," Frazier said. "But we're only in June, so I have to temper my emotions a little bit."

-- June 6