The record of a football team can vary wildly from year to year even if nothing about the team really changes, which makes prognosticating hard. The first step for me in determining a baseline for a team's true talent is to look at points scored and points against (its Pythagorean record) but even that isn't perfect as a team can undergo profound changes over the course of a season. The second step is figuring out what offseason changes (everything from schedule to coaching to personnel) will have positive and negative effects, and how large those effects will be.

This is especially tricky with the 2015 Minnesota Vikings. On the surface, they look like an open book. They finished 7-9 last year, which was, conveniently, also their Pythagorean record (7.5-8.5) and so this seems easy, but as with all statistics context is important. Many will point to the fact that the Vikings wins came against a truly sorry bunch and discount them for that. Some will point out that their "up-and-coming" defense didn't actually fare so well in some advanced metrics, and ranked a downright bad 23rd in DVOA.

On the other hand, Teddy Bridgewater appeared to improve greatly as the season went on and his strong finish brings hope to all the Viking faithful. They will see the return of all-world running back and not-very-good-person Adrian Peterson, a huge step up from the likes of Matt Asiata. They will hopefully see a young defense stacked with some exciting players continue to gel.

So what is truly important about the Vikings this year and what is simply noise? Let's take a look.

Defense

I make use of PFF and Football Outsiders statistics in tandem because they attempt to tell you two different things, and you can often learn a lot from the discrepancies. I'm certainly not alone in projecting the Vikings to take a big step forward this year, but I am probably one of their loudest advocates, and one of the big reasons for my optimism has to do with one of these discrepancies.

Pro Football Focus graded the Viking defense very highly last year as a unit. They were a "green" 54.0 overall, composed of a very good +36.6 grade on run defense, a perfectly fine +9.0 in pass rush, and a pedestrian-but-fine +8.1 in pass coverage. Football Outsiders, on the other hand, hated their defense with a passion. They ranked 23rd in Weighted Defense, just slightly better than the Raiders. Stranger still, FO loathed their rush defense in particular, where they only ranked 25th. So what exactly is going on here? If we take these numbers at face value, the story we see is that the individual Viking defenders were doing a fine job in execution (which is what PFF measures), but that execution wasn't leading to efficient production (which is what DVOA measures). There are several reasons this can happen, and if you're truly executing correctly, simple luck is probably in the mix, and the Vikings were indeed unlucky.

The Vikings were bad defensively in some very specific - and high leverage - situations. They were 29th in goal-to-go defense, per DVOA. They were 28th defensively in late and close situations. Perhaps most importantly, they were 24th in creating turnovers.*

*Source: Football Outsiders Almanac 2015, which also explains very clearly why these are all likely to regress to the mean, so don't bother using that argument in the comments.

Struggling in these specific categories can make even a great defense seem poor, and sometimes it literally just happens for no reason. Good defenses tend to be good all the time, but if you run into some bad timing (or bad "cluster luck"), it can cause a disproportionate impact on your overall production. A good defense will not have these struggles forever. They will very likely improve in all of these categories just on regression to the mean, and if that happens, their actual defensive effectiveness should take a huge step forward.

The other major factor the Vikings have going for them is that they are a young defense that continues to get younger, and almost every young player has looked average at worst to this point, with several stars-in-the-making just getting going. Second year linebacker Anthony Barr is one of those stars in the making. He is an extremely fast, powerful linebacker who excels at getting to the quarterback and disrupting the line. Sharrif Floyd is an amazingly athletic monster at defensive tackle, having just lead the team in PFF score in his second season, and in just 587 snaps. Third year safety Harrison Smith was a standout performer in the secondary, anchoring an improving pass defense.

Mike Zimmer prefers young, athletic, fast defenders. His defenses can be undersized, they can often be run on, but they thrive on taking away the deep ball and immediately swarming to everything underneath. Against a Zimmer defense, every pass is dangerous. They allow short stuff with the knowledge that if you have to run enough plays against them, they'll eventually end up with the ball. That said, you cannot have too many large holes in what is essentially a bend-but-don't-break defense and there were two big holes in the defense last year that contributed to their lackluster numbers.

First, Chad Greenway started showing his age. The now 32-year-old weakside linebacker has been a good player for most of his tenure, but last year he started to look like more like AJ Hawk than Chad Greenway. Zimmer has steadfastly refused to criticize Greenway and recently stated that he was the best looking linebacker in camp, but every scout and statistical indicator in the world says otherwise. Maybe Greenway, like A.J. Hawk, holds onto the position based on some nebulous idea about leadership or play-calling, but it's very likely his role is scaled back. His likely successor, Gerald Hodges, is already on the roster and was stellar last year in limited action before suffering a hamstring injury. Hodges is a well-rounded player who excels in pass coverage, a skill that is particularly useful in the NFC North. If Hodges isn't your cup of tea, the Vikings used a second round pick on linebacker Eric Kendricks out of UCLA, a player I would compare to a young Chad Greenway.

The other huge hole was all 932 snaps of Brian Robison. Robison, like Greenway, has been an extremely productive player in the past, and like Greenway, he took a huge step backward last year in all aspects of the game. He's always relied on speed as his primary weapon, but at 32 he's lost a few steps and was ineffective as a pass rusher. He's never been a stalwart in run defense, and the end is likely to come quickly for Robison. If you're looking for a replacement I'd put my money on rookie third round pick Danielle Hunter out of LSU. Hunter is raw, but he has the kind of athleticism that Zimmer loves on his defense.

The Vikings also needed to address depth in the secondary, as they do have a few weak spots in the back four. In sticking with the theme of athleticism over everything else, they used a first round pick on Trae Waynes out of Michigan State. I am not a fan, as I think Waynes is a sloppy player who excelled on his physical gifts without learning how to play cornerback properly, but if the Vikings can coach him up, he could be another dangerous weapon.

The Viking defense had a rough season last year given the talent on the team, but they've taken steps to make upgrades in every key deficiency. While it's possible that some of those moves will not work out, it's always a good sign when a front office understands what their weaknesses are and takes steps to correct them.

Offense

The one thing we know for sure is that the Vikings get back all-world running back Adrian Peterson, whom I believe to be a despicable person, though that's outside the scope of this article. The good news for the Vikings on the field is that he is a huge upgrade over both Jerick McKinnon and Matt Asiata in terms of pure running back talent if healthy. That said, he may not be quite as big of an upgrade as you would expect. Matt Asiata actually ranked 17th in DVOA last year (1.0%) and had a stellar 52% success rate (6th in the league). McKinnon actually ranked 7th in DVOA at 11.5%, just a tad better than one Eddie Lacy (also keep in mind that DVOA is a per-play rate stat, not a measure of total production like DYAR). McKinnon is an interesting prospect. Pro Football Focus largely agrees with DVOA as to his running, scoring him at +3.3 (which is good for a true split-time back), however he gave back all of that value and more in the passing game, as he was an atrocious blocker and poor receiver.

So Peterson returns to a situation where the running itself was by-and-large pretty good, while the secondary running back skills (i.e. blocking and receiving) were poor, and this may limit his ability to offer a huge upgrade in production to the team. Truthfully, Adrian Peterson is also terrible as a blocker and as a pass receiver, and has been for several years now. His receiving DVOA in 2013 and 2012 was -22.8% (45th among RBs) and -14.8% (33rd among RBs) respectively. His PFF grades reflect this reality as he has not scored better than average in the passing game in years, and as much as they dislike his receiving, they hate his blocking even more.

Peterson's main contribution will be the big play. This is nothing to sneeze at, but I suspect he won't take as much pressure off of Bridgewater as people think. Bridgewater has basically lacked a true safety valve at the position and unless DuJuan Harris makes the team and shows some chops as a receiver, this will remain the case. His backs will still be unreliable blockers, and their success rate (which tells you how much the RB has contributed to picking up a first down) will remain about the same.

Peterson will at least be a definitive if limited upgrade. Mike Wallace is another issue entirely. Wallace made his name as a stand-out Steelers receiver many years ago, but since 2011 he has been pedestrian to downright bad. In roughly the same number of snaps, he actually graded lower than Greg Jennings last season (0.0 to -0.9). Wallace was more productive than Jennings last year and they don't really do the same job, but Wallace can be a very frustrating player for a quarterback. Ryan Tannehill is regarded by many scouts as having an excellent deep ball, but his production numbers have never managed to keep up with his scouting grades. This is largely due to Wallace's drops and his extremely low catch percentage. I would wager there is no one happier to see Wallace move on than Tannehill, who will coincidentally now be targeting Greg Jennings.

I doubt the Vikings will get worse on offense, and I think to the naked eye they will appear to be more exciting, but I don't think they will get much better absent a big improvement from Teddy Bridgewater. I also think this is fairly likely to happen. Bridgewater played brilliantly in the second half of the season and while such a small sample size isn't definitive of anything, I don't think it was just randomness. There were other factors that lend credence to the idea that the improvement for Bridgewater, and the Vikings as a whole was real.

Bridgewater started the season on the bench, started playing in week 3, and was basically a caretaker quarterback for a few weeks, partially to ease him into his new role and partially because he was still learning. He was also cursed with an awful supporting cast. In his first start his leading receiver was Jarius Wright; Cordarelle Patterson, who I'm happy to label as an all-out bust, was still prominently involved; and Kyle Rudolph was hurt. Fast forward to week 10 and things look different. Rudolph is back on the field, Charles Johnson basically took Patterson's role, giving the Vikings an actual dynamic field-stretching threat, Wright and Jennings continued to be solid if unspectacular, and Bridgewater started to blossom. Even his error-filled effort against the excellent Lions defense in week 14 contained several moments of brilliance. When given actual targets to throw to, he was generally on time and accurate with the ball. According to PFF, in the last eight games of the season Bridgewater was only graded below average once, and it was against said excellent Detroit defense. He was graded green (meaning "good") five times, and not just against porous defenses.

Bridgewater may never be Aaron Rodgers, but what is more important for now is that he's paid like a rookie. He only needs to be average for the Vikings to have success, and in my opinion, outside of Andrew Luck there is no young quarterback with more potential than Teddy Bridgewater.

Conclusion

The Vikings are probably a true talent 9-7 team, but one with significant upside. If Bridgewater is merely average they should be wild card contenders, but with a little luck and additional development, they can be much more. If you are looking for the team that is likely to be the thorn in the Packers' side for the next several years, look no further.