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 2:45 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.

CORNERBACKS

Currently on roster: 10

Likely to make opening day roster: 6

Certain to make the team: Chris Cook, Xavier Rhodes, Josh Robinson

On the bubble: A.J. Jefferson, Jacob Lacey, Bobby Felder, Marcus Sherels, Brandon Burton

Practice squad candidates: Roderick Williams

Camp depth: Greg McCoy

Biggest offseason developments: In a move that surprised just about everybody, the Vikings released 14-year veteran Antoine Winfield on the opening day of free agency, hoping to rid themselves of Winfield's $7.25 million salary for this season and wanting to potentially re-sign him at a deep discount. A month later, Winfield signed a one-year deal with the Seahawks. … The Vikings used the 25th pick in April's draft – one they acquired from Seattle in the Harvin deal – to select Rhodes.

What we'll be watching: This may be, perhaps, the scariest unit for head coach Leslie Frazier to analyze at this point. Sure, there's a ton of young talent and plenty of promise. But what happens if Cook can't stay on the field after missing a total of 26 games in his first three seasons? What happens if Rhodes needs extra time to get up to speed with the NFL game? What happens if the efforts to get Robinson comfortable playing in the slot in nickel packages doesn't click in immediately?

Frazier, defensive coordinator Alan Williams and secondary coach Joe Woods all have superb reputations when it comes to developing young talent at cornerback. This group will certainly put that to the test.

This cornerback group seems to be talented and deep. But it's still full of ifs. By November, it could be an ascending unit and one of the emerging strengths of the defense or it could be an Achilles heel exposed by a schedule that includes tests against the following quarterbacks (in order): Jay Cutler (Weeks 1 and 13); Matthew Stafford (Weeks 2 and 17); Ben Roethlisberger (Week 4); Cam Newton (Week 6); Eli Manning (Week 7); Aaron Rodgers (Weeks 8 and 12); Robert Griffin III (Week 10); Russell Wilson (Week 11); Joe Flacco (Week 14).

Without stability at corner, things could get ugly in a hurry.

On a sleeper note, we'll be keeping an eye on second-year guy Bobby Felder, a favorite of the coaching staff's who could be ready to earn a spot on the 53-man roster after spending last season as a practice squadder.

Star Tribune offseason excerpt:

According to an NFL source, the way Winfield's dismissal unfolded proved incredibly awkward. Cold even. And those are the nice ways of putting it.

Winfield was at Winter Park on Tuesday routinely working out. Approximately an hour before the NFL's free-agency period opened at 3 p.m., he was summoned upstairs and told he had been cut.

The discussion was brief and unceremonious, the kind of sobering transaction players always are bracing for but never ready for.

"It was a business decision as we move forward," Spielman explained later.

But then the Vikings GM hinted he wanted to "keep the door open on [Winfield's] possible return." And he echoed that sentiment six times during a 15-minute presser.

Yet that "door could still be open" rhetoric felt like a hollow formality to Winfield and his agent, neither of whom had received any contingency plans when communicating with the team 90 minutes earlier.

They were simply led to believe this was likely the end — harsh but necessary."

– March 13

SAFETIES

Currently on roster: 7

Likely to make opening day roster: 4-5

Certain to make the team: Harrison Smith, Jamarca Sanford, Mistral Raymond, Robert Blanton

On the bubble: Andrew Sendejo

Camp depth: Brandan Bishop, Darius Eubanks

Biggest offseason developments: The Vikings didn't let Sanford get away in free agency, bringing him back on a two-year deal worth up to $5 million.

What we'll be watching: Smith is Sharpied in as a starter at one safety spot but there's no telling who will be alongside him. Raymond was the opening day starter in 2012 but was injured in Week 3 against the 49ers and never earned his starting role back. Instead that slot was held down by Sanford, who was the starter when training camp opened last summer but was demoted before leaving Mankato. Sanford not only never sulked after that move, he remained ready to take a big step up when called upon and delivered a season that impressed everyone within the organization, an intangibles guy who makes up for many of his coverage deficiencies with his toughness, hunger and overall enthusiasm.

Sanford will try to keep his grip on that starting spot alongside Smith as long as he can. But don't think Raymond and Blanton will settle into back-up roles without a fight.

Given the tenacity of this position group to begin with, they were going to provide some pretty entertaining camp moments. With a three-man battle for a starting spot on the line, the intensity will only spike.

Star Tribune offseason excerpt:

Sanford's energy is contagious and he continues to draw praise as a guy who embodies the unselfishness, toughness and passion that Vikings coach Leslie Frazier is looking to build around.

But … (And you knew a but was coming right?) While Sanford may start training camp as the designated starter, he doesn't have a stranglehold on that role. Far from it.

Frazier understands Sanford is a special teams ace and may be at his most valuable overall if allowed to concentrate more on that role. Plus, there are not only high hopes for Raymond as a guy who has more promise in coverage, but it's not unforeseeable that Blanton could take a huge leap forward and perhaps end up starting alongside Smith before this year is over.

Blanton pressed through a conversion from cornerback to safety last year but also impressed the coaching staff with his ability to quickly pick things up.

"As the year went on, he made strides understanding space and angles from the safety position," Frazier said. "And he plays with a high motor. He plays 100 miles per hour at all times."

– April 20