For the Braves' recent struggles, Frank Wren must fire manager Fredi Gonzalez and hitting coach Greg Walker.

Let me say that again.

The Atlanta Braves must fire Fredi Gonzalez and Greg Walker.

When assessing what went wrong in a season that started with such high expectations, there is plenty of blame to go around. There have been failures compounded by failures that have ultimately led us to this point. This column is not meant to place all the blame on Atlanta's coaching staff. But they certainly deserve a healthy share. From his curious bullpen usage, to his maddening lineup construction, to the regression of almost every Braves hitter, Fredi Gonzalez is front and center when it comes to assessing responsibility for this season's failings. Greg Walker is not far behind.

As I write this, the Nationals are currently celebrating reclaiming the NL East crown from Atlanta in the bowels of Turner Field. The Braves sit a game under .500 for the first time in September since 2008. And they now sit 5.5 games out of the second Wild Card with 11 left to play. It's no longer a race; it's a victory lap for the Pittsburgh Pirates.

The most glaring difference - to me - between this year and last year is the almost universal regression of Atlanta hitters. Let's take a look at the wOBA of all Atlanta hitters who had >90 plate appearances each of the last two years. For those of you who aren't familiar with wOBA (weighted on-base average), it is one of the most popular and well respected "catch all" offensive statistics. At the risk of oversimplifying it, consider it a version of OPS that properly weights different at-bat outcomes in terms of run values. You can read more about it here.

That's almost painful to look at. Of the 11 hitters who have had significant plate appearances with the Braves over the last two years, only three saw their wOBA increase from last year to this year. An additional two (Freeman and Heyward) stayed around the same level. The rest...woof.

So, is this all random noise? Did many of these guys just simply have career years last year? That's certainly a possibility, but fortunately we have statistics to help us out! We can use a paired sample t-test to determine if the difference between 2013 and 2014 is statistically significant. This examines the observed differences between each batter to determine what the likelihood is that the differences are just due to random chance. (After all, everyone in baseball has up years and down years.) After calculating the test statistic, we find that our test has a p-value of ~0.03.

This means that the probability of obtaining a difference as extreme as the one we saw between 2013 and 2014 is roughly 3%. This value is small enough to be considered statistically significant. In other words, we can be reasonably sure that the drop off in offense from 2013 to 2014 was not the result of random chance.

Because this is an observational and not a controlled study, we can't say for certain what the cause was of the decline. But we can make some educated guesses. And if I had to guess, I'd say the coaching had something to do with it. Under Greg Walker, the Braves had not made any secret that they are trying to strike out less. (One wonders how much of this was spurned by the ridiculous narrative that strikeouts are awful, but that's a thought for another day.) So, instead of waiting for their pitch and driving it like they did in 2013, the Braves are instead expanding their zone in an attempt to make contact.

But here's the problem: if you're reaching to make contact, chances are the contact you do make won't be very authoritative. And the numbers bear that out. From 2013 to 2014, the Braves groundball percentage increased from 43.5% to 45.5%. And that's not a good thing. After popups, groundballs are the least desirable type of contact. Opposing defenses turn ground balls into outs at a roughly 80% clip. Plus, groundballs are more likely to make multiple outs. Fly balls go for hits about as often as groundballs, but they have a chance to go over the wall. So, basically, the Braves have sacrificed power to try and make more contact. And they've sacrificed a ton of it. A year ago, the team's ISO (Isolated power, which is slugging percentage - batting average) was .153. This year, it sits at .122. And they're walking less too: 7.9% of plate appearances down from 8.8% last year. And here's the kicker: strikeouts have not changed. In fact, they've actually gone up a bit! (22.4%->22.6%) How anyone believes this is a model for success is beyond me.

This, to me, is the biggest reason that Fredi Gonzalez and Greg Walker must go. They abandoned what was a successful offensive ideology because of a fabricated narrative, and the team has suffered dearly for it. A year ago, Andrelton Simmons's bat made him look like a potential MVP. Now he's totally lost at the plate. Atlanta's recently-extended third baseman can't seem to do anything but helplessly roll over pitches to second base (if he even makes contact with them.) Not only has such a damaging philosophy cost Atlanta wins this year, but it could (continue to) significantly hinder the development of the organization's young talent.

Atlanta's management has bought in to a model of hitting that encourages batters to make weak contact over striking out, and the team's offense has paid the price.

This is the most egregious of Fredi Gonzalez's sins, but it is far from the only one. I could talk about his vapid lineup construction, which has seen BJ Upton receive more at-bats in the #2 spot than any other hitter. (For those of you who are unaware, the statistical consensus is that the team's best hitter should hit #2.) I could talk about his excruciating use of the bullpen, which has seemingly no grasp on the concept of leverage. I could talk about his patterns of substitution, which fetishize a Quad-A outfielder who does nothing well over several legitimate prospects.

Some people will tell you that lineup construction doesn't make that much of a difference. They're correct, in the grand scheme of things. But given that his bone-headed hitting philosophy has already neutered Atlanta's offense, doesn't it make sense to try and maximize your advantage in any way possible?

Some people will point to his win total with the team, but that is a clever sidestep of the issue. Dusty Baker could have won roughly the same number of games with a team so talented.

None of these problems are that terrible in a vacuum. But taken together, they paint a picture of someone who is woefully overmatched at best and willfully ignorant at worst.

Again, the failings of Atlanta's 2014 season do not rest solely with Fredi Gonzalez. The construction of Atlanta's bench was not well done, and that falls on the front office. Freak pitching injuries happen. But at the end of the day, Fredi Gonzalez's failings are just too much to ignore.

It's time for the front office to tip their caps and send Gonzalez and Walker on their ways.