Updated

The Minnesota Vikings have reached a crossroad, coming off a remarkable season during which they improved by seven victories, made the playoffs and watched Adrian Peterson transition from ACL rehab patient to MVP award winner.

Slip back a bit, and 2013 will likely be widely viewed as a disappointment. To pick up where their progress left off last year, though, the Vikings will need just as much to go right as in that surprising 2012 season. Similar to last year, when they were coming off a 3-13 mess, the Vikings have again set out amid skepticism from analysts and fans about whether they're built to stay on a title-contending track.

By the end of 2013, they'll know whether last season was simply a fluke or a foundation for the future.

"Super Bowl: I know that's the goal as a group," Peterson said at the end of minicamp. "I feel like we've got the right pieces in place. Everyone has that vision in their mind."

Five things to know about the Vikings as camp begins:

1. PONDERING THE FUTURE: Christian Ponder will be the starter when the Vikings open at Detroit on Sept. 8. But he has a lot to prove before his status is ensured for next year, let alone for the rematch against the Lions that wraps up the regular season on Dec. 29. This time, the Vikings have a better option as a backup in Matt Cassel. General manager Rick Spielman has often said he needs three years to evaluate quarterbacks, bringing the former first-round draft pick into a crucial window. Not only does Ponder have a stronger offensive line, his receivers have been upgraded over that span, too, despite the departure of the do-it-all Percy Harvin. Greg Jennings was signed from Green Bay to be the leader, Jerome Simpson was brought back on another low-risk one-year contract and Cordarrelle Patterson was selected with the third of three late first-round draft picks. Tight end Kyle Rudolph, the Pro Bowl MVP, will also be relied on even more as a down-field weapon. "Christian, I'm excited. He's a great quarterback. He's going to shock people," Jennings said last month.

2. ALL DAY CAN GO ALL YEAR: Peterson left no doubt about his determination, focus and seemingly superhuman skills by returning from reconstructive surgery on his left knee to rush for 2,097 yards, 9 short of the NFL record. If Ponder can improve, the Vikings offense should be more balanced, which would make cracking the 2,000-yard mark again even more challenging for Peterson. But he's one of the rare players for whom any feat seems possible.

3. UNDER THE DOME: The Vikings have long enjoyed a significant advantage under the noisy Metrodome's roof on the spongy artificial turf, but this is their last year in the quirky, outdated stadium. They'll play two seasons outside at the University of Minnesota before opening their new indoor venue in 2016. They'll also have one fewer home game this fall, too, when they "host" the Pittsburgh Steelers in London on Sept. 29.

4. THE NEW DEAL, ON THE DEFENSIVE LINE: The front four has long been a strength of this franchise, from the Alan Page-led Purple People Eaters to the era of Hall of Fame pass rushers Chris Doleman and John Randle to the current group led by Jared Allen. But Allen, fellow defensive ends Everson Griffen and Brian Robison and stalwart defensive tackle Kevin Williams have all begun the final year of their current contracts. Given age, productivity and salary cap factors, envisioning all of them still around in 2014 is all but impossible. So not only will these guys need to re-establish their worth, for either their present employer or other teams on the open market, but the Vikings themselves must make some important decisions about who to invest in for the future. First-round draft pick Sharrif Floyd is in line to replace Williams, a six-time Pro Bowl pick.

5. STILL UNDER SIDELINE SCRUTINY: Despite the feel-good vibe and vast improvement he helped produce last season, Leslie Frazier hasn't yet secured his future with the franchise. The Vikings routinely exercised their option for 2014 on his contract, but since coaches rarely enter the final year of a deal without an extension, this is another prove-it season for Frazier, a subject he has tread carefully around in public.

___

Follow Dave Campbell on Twitter: www.twitter.com/DaveCampbellAP

___

Online: AP NFL website: www.pro32.ap.org