When Pat Fitzgerald walked into his postgame press conference after a 45-6 Outback Bowl thrashing at the hands of Tennessee, something seemed off. Fitzgerald was upbeat and positive. When asked about the offense's struggles, he in part refuted the question, saying, "You're talking about stats, and the only stat that matters to me is winning, and we won 10 games."

The general message from the program was that a 10-win season is a 10-win season, and despite its unpleasant ending, it should be celebrated. And it's true. The Outback Bowl loss doesn't completely tarnish the success of September through November, which started with an upset of Stanford and ended with a reclaiming of the Land of Lincoln Trophy.

But whereas the Outback Bowl didn't reflect the season as a whole, the offensive performance did. Clayton Thorson threw for 57 yards-- the fewest of his career-- and two interceptions, and the offense gained just 3.18 yards per play with Thorson at the helm. It was the culmination of a season of frustration on that side of the ball. One Northwestern fan even went so far as to compare the offense to Kobe Bryant — effective 15 years ago, but now slow, predictable, (inefficient) and really hard to watch.

That fan ended the tweet with a simple hashtag: #FireMcCall. Oh, and he wasn't the only one. Calls for offensive coordinator Mick McCall's firing were more (digitally) audible than ever Friday. Despite a 10-2 regular season, Northwestern's offense was pitiful the entire year, finishing 111th out of 128 teams in S&P+, and 109th in FEI. The Wildcats often won despite their offense and in no way because of it.

So despite the 10 wins, the question is an entirely fair and relevant one: Should head coach Pat Fitzgerald, who has control over staffing decisions, fire McCall?

First of all, it's important to define what the relevant question actually is. It's not a question about the past. It's a question about the future. Both sides of the argument draw on the past for evidence, but you don't fire a coach for past failures. Rather, you fire him for expectation of future failures, or a lack of confidence in future success. The question is, does retaining McCall as offensive coordinator give Northwestern the highest probability of future success?

On the surface, the past few years seem to clearly suggest it doesn't. The offense has fallen in adjusted yards per play rank every year since 2011, when it was 36th. This year, it sunk all the way to 113th out of 128, the fourth-worst mark among Power Five teams. Last year, with an outstanding running back, a quarterback that was drafted, and three other players on offense that made NFL training camp rosters, it wasn't much better, ranking 104th.

McCall's Northwestern offenses by year Year Adj YPP Adj YPP rank Raw YPP Raw YPP rank 2008 5.18 70 4.89 89 2009 5.15 83 4.98 93 2010 5.29 69 5.38 69 2011 5.86 36 5.59 50 2012 5.5 59 5.27 86 2013 5.65 63 5.37 75 2014 4.84 104 4.52 122 2015 4.63 113 4.39 120

McCall, who is both the offensive coordinator and the quarterbacks coach, has come under fire in recent seasons because of the decline, and for other, more specific reasons. The offense has seemingly become predictable. The play-calling has, in the opinion of some, been poor. McCall hasn't been able to craft a scheme that fit his personnel. He also doesn't appear to have done a good job developing quarterbacks over the past three or four years.

In a general sense, he hasn't been able to capitalize on the players at his disposal. The offensive nosedive has occurred while the talent in the program, at least on paper, has increased. Furthermore, per 247 Sports' rankings, four of the top six players in the 2012 class, three of the top seven in the 2013 class, and six of the top seven in the 2014 class were offensive players, so it's not like recruiting on one side of the ball has lagged behind the other.

However, it was clear that talent on the offensive side of the ball was severely lacking for Northwestern in 2015, and for the most part, there's nothing Mick McCall can do about that. Five offensive players from the 2012 and 2013 recruiting classes have since left the program, and multiple others didn't or haven't yet panned out due to injuries.

There have also been striking deficiencies in player development on the offensive side of the ball. At the quarterback position, that's on McCall, if it's on the coaching staff at all. Zack Oliver spent five years in the program and never was able to win a starting job. Matt Alviti was a celebrated recruit, but has spent three years in the program and hasn't even reached No. 2 on the depth chart. And while it's far too early to judge Clayton Thorson, he had a rough redshirt freshman campaign despite his natural talent.

More glaring have been the issues on the offensive line and at wide receiver. Offensive line coach Adam Cushing has been with the program for 12 years, but only took over as the offensive line coach in 2009. In recent years, the development of offensive linemen has been inadequate. Guys like Shane Mertz, Adam DePietro, Kenton Playko and Sam Coverdale haven't fulfilled supposed potential. Plus, the mishandling of Geoff Mogus (moving him from guard to tackle this offseason) and the constant shuffling and position switches are worrisome.

So should Cushing be under pressure? Probably. Even if you think back to Brandon Vitabile, the best NU lineman to play all four years under Cushing, did Vitabile really develop that much from his freshman and sophomore years to his senior year? Was he that much more effective late in his career, even with added size and strength? Cushing's performance has been questionable at best.

Another position coach who can be questioned is Dennis Springer. Springer took over as wide receiver coach when Northwestern lost Kevin Johns to Indiana in 2011. Springer's units have been unlucky with injuries, most notably those to Tony Jones, Christian Jones and Kyle Prater, but players like Mike McHugh, Cameron Dickerson and Pierre Youngblood-Ary didn't become anywhere near the players they could have been. Some portion of the underdevelopment is on the players themselves, but Springer probably shoulders some of the blame too.

Northwestern's receivers have been downright awful for two years, and that greatly hinders any offense. Couple the receivers with a struggling offensive line, and it's a recipe for disaster. If an offense doesn't have receivers that can get separation and win individual battles, opponents can play them one-on-one with only a single high safety over the top. Northwestern saw that a lot in 2015, and couldn't beat it:

(Videos courtesy of Big Ten Network)

Even when teams would sit back and play coverage, Northwestern would also struggle. No matter what McCall did, underneath routes would be defended, and the offensive line would allow three- and four-man rushes to get to Thorson:

Whenever possible, McCall would rightly try to establish Justin Jackson and the running game, the offense's best weapon. But against eight-man boxes, with an offensive line that couldn't get a push, that was, at times, near impossible:

Receivers who can't get open or make tough catches can single-handedly ruin an offense. Without a deep threat that could beat man coverage, Northwestern was basically playing red zone offense up and down the field. It couldn't stretch teams vertically. And with a quarterback who couldn't run the speed option and struggled in the read option, Northwestern couldn't stretch teams horizontally either. To some extent, McCall was helpless.

McCall was heavily criticized all season for the predictability of his play-calling. He would run the ball too much on early downs, frustrated fans said. But then when he would come out throwing on first and second down, get forced into a third-and-long, and go three-and-out on three incomplete passes, he was also criticized. He was labeled too conservative when he would run on third-and-long, but was also criticized when Thorson would throw into coverage in those same situations. That's all outcome-based analysis, and isn't fair.

The fair criticism is of the scheme. As former Northwestern linebacker Nate Williams wrote after the Iowa game,

Everyone who takes issue with the offense is wondering why we run on first down, and asks why we "don't pass on first instead" and get "more creative." That's not sound judgement, thinking, or critiquing. We do not need "creativity." We need to revamp our entire strategy. There is a script the offense has for at least one or two drives per game. When the script goes wrong, it's over. Other than the said scripted drive, there's no setup game, no "gotcha" moments. There is no "okay, we ran this against this look and saw them overcommit, so let's run something else, take advantage of that and rip a big one." Its simply, "what play works and what play does not against said look," and run what is perceived to work.

The offensive scheme is clearly somewhere between 'not working' and 'broken.' Even with the lack of talent, there are ways to move the ball better than Northwestern has. McCall's offense hasn't evolved in a meaningful, positive way. It's safe to say that McCall's performance over the past two years hasn't been adequate.

But remember, we're not solely considering the past. We're considering the future. If we accept that McCall might not be as responsible for the offense's shortcomings as some think, and we consider the success of 2011 and the surrounding years, perhaps the last two years can be seen as aberrations. Or perhaps they can't.

That's the thing. We don't know. Good decisions don't always lead to success. You can choose to do something that is successful 90 percent of the time, but 10 percent of the time, it won't work and will look bad. But if it does, that doesn't make it the wrong decision.

By the same token, good coaching doesn't always lead to success. An offensive staff could recruit good players and teach correct techniques really well, but if those players have injuries, or off-field problems, or just don't have the drive to improve, that offense isn't going to be successful. But the fact that it's not doesn't necessarily mean the coordinator is doing his job poorly.

What if McCall has been making the optimal decisions all along, they just haven't been working out recently? It's actually a possibility. Of course, there's also the possibility that he's been making sub-optimal decisions all along, but in earlier years, he got lucky and they worked out for him. There's no way to tell.

The problem is that it's difficult to separate all those factors from each other. Coaching failure, player failure, system failure and other uncontrollable factors are all intertwined. So there's no way to definitively adjudicate whether the failures are due to McCall, or to his position coaches, or to other factors, and thus there's no way to definitively say whether moving forward with McCall or making a change is the correct decision. As SB Nation's Spencer Hall wrote in an article titled The case for not changing a damn thing,

Doing the same thing over and over again might be insanity, or it might be exactly what you need to do, and the fun part is that you'll never know where you are between the two.

As I write, as you read, and over the next week or two, Pat Fitzgerald will be trying to figure out where he and his offense are between the two. Chances are, due to the team's 10 wins and Fitzgerald's unquenchable thirst for continuity, he'll decide he's closer to the latter. McCall will be retained. All of his position coaches might be too. And there is at least some reason to believe that things could turn around as soon as next year.

But that's probably not a strong enough statement to rationalize retaining the entire staff. It's not that there's no chance McCall and his assistants could eventually be successful again at Northwestern, and it's not that a partially new offensive staff is guaranteed success. But the recent trend has been negative enough to suggest that the new staff would probably give Northwestern a higher probability of success in 2016 and beyond.