Variability is a rebuilding team's best friend and a baseball forecaster's worst enemy.

Anyway, that seems to be the case for the 2017 Milwaukee Brewers and all those who consigned them to the lower tiers of the big leagues before the season.

My hand is up, by the way. My system had the Brewers at 72 wins before the season, a total they reached the day before Labor Day.

Subjectively, I realized there was a lot of potential in the organization, but the lineup had too many issues with making contact and the roster just didn't have enough pitching, or so it seemed, and the Brewers didn't make any significant additions in that area during the offseason.

How they surprised us

When it comes to predicting run totals, the run prevention side of the equation is probably close to 50 percent more difficult than run scoring. It's just the nature of pitching, of its uncertain development patterns, susceptibility to injuries, of its still-unclear relationship to the defense around it. Hence, variability. This is what I was thinking about this weekend when I read this old quote from the introductory news conference of Brewers GM David Stearns in the Milwaukee Journal-Sentinel:

"I'm a big believer in not setting limits for any team, for any year," Stearns said. "This is a game with a tremendous amount of variability, and we're going to take each decision as it comes, and make each decision in the best interests of the overall health of the organization. The product on the field is a large component of that."

It's a good product, but in the case of Milwaukee's pitching, it only made sense that any set of objective projections would slot the Brewers near the bottom of the majors. Last year, they ranked 13th in team ERA. That's not terrible, but it looked worse when you got underneath the hood.

According to Fangraphs, Milwaukee's fielding-independent ERA (FIP) ranked just 22nd and its xFIP (FIP normalized for home run-to-fly ball rates) was 26th. The divergence was explained by the fact that only two teams had a lower strikeout rate than Milwaukee.

Metrics like FIP and xFIP are typically more predictive than basic ERA, so that's why my forecasts ranked Milwaukee just 27th in run prevention coming into the season.

News flash: The Brewers rank eighth in runs allowed this season. Their FIP ranks 12th, their xFIP ranks 10th and, most remarkably, their strikeout rate has climbed from 28th to 11th. What's so remarkable about that? Stearns simply replaced a bunch of finesse guys with strikeout guys, right? No. That's where this gets interesting.

Consider the year-to-year numbers of the Brewers' top four pitchers.

Numbers Of Brewers' Top Four Pitchers PITCHER IP (2016) SO/9 (2016) FIP (2016) IP (2017) SO/9 (2017) FIP (2017) Zach Davies 163.3 7.44 3.89 180.3 6.04 4.09 Jimmy Nelson 179.3 7.03 5.12 175.3 10.21 3.05 Chase Anderson 151.7 7.12 5.09 128.0 8.44 3.58 Corey Knebel 27.7 12.36 3.58 70.0 15.30 2.13 TOTAL 522.0 7.47 4.64 553.7 9.09 3.39 Top four by Fangraphs WAR

This foursome -- Milwaukee's top three starters and its closer -- accounts for 13.8 of the team's 17.4 pitching WAR through Monday's games, and that's Anderson and Knebel combined for seven shutout innings and 10 strikeouts in Tuesday's win in Pittsburgh. Davies, the one guy in the group who retains the K-rate of a finesse pitcher, has improved more subtly in that his uptick has come by getting more ground balls. But overall, this is a stark improvement from a group that no one really saw as becoming elite.

And elite they are -- only six teams currently feature a top foursome with more WAR than Milwaukee's. Well, this was the case before Nelson went down with a season-ending shoulder injury, suffered not on the mound but on an unfortunate belly flop into first base last week in Chicago.

"I think our pitchers as a staff are continuing to grow and mature," Stearns told me earlier this season. "It's a relatively young pitching staff. The guys who might be a little bit older agewise don't have a ton of major league experience, really with the exception of Matt Garza.

"It's natural as these guys gain more experience at the major league level in this division, that they become more comfortable and that their performance improves. I think that [manager] Craig [Counsell] and [pitching coach Derek Johnson] have done an outstanding job managing that segment of the roster, putting all of the pitchers, whether it's starters or relievers, in positions to succeed."

Sure, but it's tough to dismiss the Brewers' collective improvement as simple career progression because the degree of the uptick is beyond any sort of typical aging pattern, insomuch as such a thing exists.

Zach Davies is just 24 and kind of is what he is, which isn't a bad thing. Corey Knebel is 25 so, yeah, maybe he's a young guy just getting his legs at the big league level, but even that doesn't explain such a huge jump in K-rate. Meanwhile, Chase Anderson (29) and Jimmy Nelson (28) have been around for a while.

So, what's the commonality here? In such situations, it's hard to not turn your gaze toward the aforementioned pitching coach, Derek Johnson.

Baseball's newest star pitching coach

Johnson first made a name for himself by helping mentor future pros like David Price, Sonny Gray and Mike Minor while serving as pitching coach for a decade at Vanderbilt. So, he knows a thing or two about working with young pitchers.

"As much as anything, it's getting their feet wet in the big leagues," Johnson said, echoing Stearns. "And figuring out what to do from there. I think every player goes through it. Sometimes they are fortunate to stick around long enough to figure it out. These guys were in a good position last year. They got to pitch and took their turn every five days. It didn't always look great or work out perfectly for them but I think they learned a lot."

An Illinois native, Johnson eventually moved on to the professional ranks by working as a roving instructor for the Chicago Cubs, the team he grew up rooting for.

So, in that way, it's kind of ironic that Johnson has played a part, maybe even a big part, in helping the Brewers threaten the Cubs' assumed dominance in the Central. Still, he was able to enjoy the Cubs' title last season.

"It was really awesome, really special," Johnson said. "For me personally, I sat in the dark by myself and turned down the volume so I didn't have to listen to anyone's interpretation of what was going on. I watched the game. When they won, I thought of a lot of people that had a part in that."

When it comes to the uptick in the Brewers' pitching stats, it's hard not to turn to Derek Johnson, who helped Jimmy Nelson simplify his delivery. Nam Y. Huh/AP Photo

Johnson isn't a tinkerer, necessarily. He's more of a cerebral coach who listens to his subjects as much as he instructs. In fact, he's an author -- he released a guide to pitching a few years ago, with a forward written by Price. Johnson is not associated with teaching a specific pitch, as is White Sox guru Don Cooper with the cut fastball, or former Giants manager Roger Craig with the split-finger.

His work with the Milwaukee staff isn't a matter of a string of "Eureka!" moments, though his work in helping Nelson simplify his delivery -- and sticking with it when the numbers didn't immediately follow -- is enough by itself to merit recognition. Anderson has also been effusive in his praise of Johnson, as has Counsell, for that matter.

"I think he's played a really big role," Counsell said. "The guy for me to point to is Jimmy Nelson. Nelson and DJ made a pretty big delivery change about halfway through last year, and without really great results for most of the rest of the season. But they stuck with it because they both knew it was the right thing to do. It's paid really big dividends this year."

Johnson -- who is an analytics guy -- cites established pitching coaches such as Houston's Brent Strom, the Cubs' Chris Bosio and Cooper as key influences. He has found that the key for a pitching coach is to know when to interject himself, whether it be with a metric or technical suggestion.

However, it's just as important to know when to sit back and leave well enough alone. For instance, I asked him if in his Cubs days he had worked with the meticulous Kyle Hendricks in the minors. Johnson simply said, "He didn't really need much from me."

What is a pitching coach worth? It's a good question and I don't have a definitive answer. Russell Carleton of Baseball Prospectus took a look a few years ago that centered on longtime Braves pitching coach Leo Mazzone and estimated that over the course of his career, Mazzone may have sliced as much as a third of a run from his staffs' FIP. That's the elite of the elite and the product of results compiled over a long period of time. It's way too soon to say that Johnson is in that class.

"I think that as Derek has had a year or two of his program, and our program, working with these guys on a consistent basis," Counsell said, "I think the results have kind of spoken for themselves."

The early returns are definitely good and it leads me to a notion that I've been turning over in my head for a few months. That is, for any team entering into a rebuild, there may be no more important asset than a topflight pitching coach. There are a lot of duties under the umbrella of a pitching coach. There is working with veterans to make adjustments and fixes to technical issues gone awry. There is the day-to-day grind of game preparation. There is the crucial role of helping emerging young pitchers top off their development at the big league level. And there is an underrated aspect, which is if you have a pitching coach who consistently helps low-cost starters and relievers turn around their games, he gives the general manager valuable assets with which to work as the rebuilding plan goes forward.

"A good bit of it is furthering development with guys when they get to the big leagues," Johnson said. "Most guys when they come up from Triple-A, they aren't truly ready. It's no one's fault or that our minor leagues didn't prepare them. It's that every pitch is magnified here, there's more stressful pitches thrown, more stressful innings played. They really aren't ready. They have to see this thing and experience it, and we have to figure out what adjustments to make. Things to say and things to stay away from. That's a big part of it."

Brewers manager Counsell will get a lot of support in the NL Manager of the Year balloting, as he should. But perhaps the key move Counsell made actually occurred before last season, when he shook up his coaching staff and landed on Johnson as his new pitching coach.

Counsell may have struck gold.

"But really, my job is really just knowing when to poke the bear at the right time. There are things I want to say all the time and I keep my mouth shut. Other times, there are things I need to say and do. There is always that balance." Brewers pitching coach Derek Johnson

This surprise season in Milwaukee has been all about the pitching. The Brewers' offense hasn't been a surprise at all. No, we didn't exactly pencil in Eric Thames and Travis Shaw for 30-plus homers apiece. But at the team level, the Brewers' attack is pretty much what we thought it would be: an offense built on the pillars of power (second in the National League in homers) and speed (first in stolen bases).

But strikeouts are an impediment to consistency (most in the league) and while the Brewers have done better than expected in collective plate discipline (sixth in walks), the lack of balls in play means at the bottom line, Milwaukee ranks 11th in the NL in scoring, only one slot better than where I forecast the team before the season.

So, if the hitters aren't contributing to our collective surprise, then it must be the pitchers, right? Bingo. The Brewers' pitching staff is one of the most emergent units in all of baseball. Going back to the preseason forecasts as a baseline, only two groups (hitters or pitchers) have exceeded projections more than Milwaukee's hurlers, who are on pace to allow 120 fewer runs than projected. Only the pitching staffs of the Indians (156 runs) and the Diamondbacks (148) have exceeded expectations by a greater degree.

We certainly can't give all that credit to Johnson. The players themselves typically deserve the lion's share of the plaudits when they improve, and it's not as if every member of the Milwaukee staff has jumped a tier. It's never like that with managers and coaches -- some things click with some players; the same things don't work with others. The key is to bring the right kinds of players together with the right coaches, and Stearns and Counsell seem to have created the kind of culture that facilitates improvement, an important trait for any small-market franchise.

In other words, the Brewers have not just brought in players with undiscovered potential in their games, but guys who also have the capacity to be coached into achieving that promise.

"You have other guys who maybe are more established or it took them a long time to get here, so they don't let a whole lot of people in," Johnson said. "It does help when you have guys who are open to suggestion, new thoughts, new ideas. It certainly makes my job easier.

"But really, my job is really just knowing when to poke the bear at the right time. There are things I want to say all the time and I keep my mouth shut. Other times, there are things I need to say and do. There is always that balance."

Where they stand

Here we are with just two weeks to go in the 2017 regular season and the Milwaukee Brewers have a nonzero chance to win the World Series. That is not a sentence you would have expected to read at the season's outset. The sentence happens to be objectively true.

The Brewers are 3½ games back of Chicago in the NL Central and just one back of Colorado in the wild-card chase. In the simulations I ran after Tuesday's games, Milwaukee now harbors a 16.1 percent shot at the postseason, split between a 7.4 percent chance at the NL Central title and an 8.7 percent shot at the wild-card spot.

With two weeks left in the postseason, the Brewers have a nonzero chance to win the World Series, something very few would have predicted heading into this season. Dylan Buell/Getty Images

With a playoff chance comes a championship chance. Not a big one -- Milwaukee is at 0.4 percent to win it all at the moment -- but, as mentioned, it's a nonzero chance. Whatever happens, for the Brewers to remain relevant to such discussions at the 151-game mark is a remarkable turnaround story. The Brewers aren't baseball's only surprise story this year. They may not even be the biggest. (Diamondbacks? Yankees? Twins?!)

But Milwaukee's turnaround has been an interesting one in a few respects and those reasons have not only made for a fun season in Brew City, they've been illustrative of the multiforked road that characterizes the path of rebuilding.