Vikings training camp snapshot: Defensive line

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.

DEFENSIVE LINE

Currently on roster: 16

Likely to make opening day roster: 9

Certain to make the team: Jared Allen, Kevin Williams, Brian Robison, Everson Griffen, Sharrif Floyd, Letroy Guion, Fred Evans

On the bubble: Christian Ballard, Lawrence Jackson, Everett Dawkins, D'Aundre Reed, George Johnson

Practice squad candidates: Chase Baker, Anthony McCloud

Biggest offseason developments: The Vikings were stunned when star defensive tackle Sharrif Floyd, widely projected as a top 5 pick for April's draft, was still on the board when they came on the clock at No. 23. They didn't hesitate a second in making Floyd their top pick, the first of three first-rounders they nabbed. … The Vikings also restructured the contract of defensive tackle Kevin Williams, reducing his 2013 pay by $2 million and eliminating the 2014 season from his current deal.

What we'll be watching: Allen and Robison were each hampered significantly in 2012 by injuries. Allen dealt with a torn labrum in his left shoulder and a meniscus issue in his left knee for most of the season. And Robison played through an elbow injury for most of the year before a severely sprained shoulder hindered his mobility even more for the final two regular season games and the playoffs.

Those physical setbacks were a partial reason the team's sack total dipped from 50 in 2011 to 44 last season. But now both veteran ends feel as if they are back at full strength and aiming to stay as fresh as they can.

Allen's disdain for the dog days of training camp are well documented. And he figures to add at least a couple of quips weekly to reinforce those sentiments. So it won't be a surprise if the coaching staff ends up giving Allen several afternoons off during the stay in Mankato to keep him fresh physically and mentally.

On the interior, once the pads come on, we'll be eager to see just how quickly Floyd adapts and excels in the middle of the defense. And it will also be a big camp for Guion, the incumbent starter at nose tackle who will have to fend off Evans to retain that role.

All in all, Allen feels terrific. He's re-energized. He's dedicated. He's eyeing a dominant 2013 and believes he has three or four more good seasons left.

But there is also an intriguing subplot lurking.

In April, Allen turned 31. Two months earlier, he had surgeries to repair a torn labrum in his left shoulder and a meniscus problem in his right knee. And, oh yeah, he has entered the final year in his six-year contract.

So with all factors considered, could this really be Jared Allen's last season as a Minnesota Viking? A farewell tour?

To be clear, that's not Allen's desire. But it could be his reality. Which is why he refuses to spend much time thinking about life beyond January.