Last night, the Pirates won their 90th game of the season, and in the process, they clinched the organization’s first playoff berth in 21 years. You probably know that this is also their first winning season since 1992 as well, so calling this team a breakthrough for the organization is probably understating the importance of the 2013 roster. So, now that they’ve reached the postseason — or at least Game One of the playoffs — let’s take a look at how they finally overcame two decades of futility to put an excellent team together.

1. They bought into the theory behind xFIP.

The idea that a pitcher can be primarily evaluated on his walks, strikeouts, and ground balls is still a pretty unpopular opinion with a lot of people. It feels wrong to essentially ignore all the other parts of baseball, especially when you see a guy give up tons of hits and home runs and then hear some nerd with a spreadsheet explain that those don’t actually mean that he’s a bad pitcher. A lot of teams — most teams, I’d say — still prefer to evaluate pitchers based on some kind of runs allowed basis.

The Pirates, though, bought into the idea that they could build a pitching staff with fixable underachievers. Here are the ERAs and xFIPs of three of their recent pitching acquisitions in the season before they joined the organization.

A.J. Burnett, 2011: 5.15 ERA, 3.86 xFIP

Francisco Liriano, 2012: 5.34 ERA, 4.14 xFIP

Mark Melancon. 2012: 6.20 ERA, 3.45 xFIP

The Yankees paid the Pirates to take Burnett of their hands. Liriano was signed as a scrap heap free agent who generated little interest from other clubs. Melancon was just one of four players acquired in the Joel Hanrahan trade, a guy who was seen as a bit part in a minor transaction. The Pirates are paying about $13 million this season for the trio, which is equivalent to the price the Red Sox paid this year for Ryan Dempster or the Nationals paid for Rafael Soriano. Those three pitchers have combined to throw 409 innings and post a 2.86 ERA for the Pirates this season.

Clearly, not even a 100% devotion to the predictive power of xFIP would have forecast this kind of performance from these pitchers. Liriano’s ERA is nearly a run and a half below his 2012 xFIP, so while his peripheral statistics pointed towards an improvement, it would be dishonest to suggest that his numbers said that this was on the horizon. Same with Melancon, who looked like a potentially solid middle reliever by xFIP but has turned out to be a dominating relief ace instead.

In all three cases, though, the Pirates chose to buy low on a talented arm who had seen his stock fall because of things that could reasonably be expected to not continue. Those moves gave them two frontline starting pitchers and one of the best relievers in the National League this season. It doesn’t always work out this well, but buying low on pitchers with inflated ERAs is still a pretty good idea, and the Pirates are prime evidence of how well this strategy can pay off.

2. They cultivated a superstar.

Andrew McCutchen was drafted 11th overall in 2005 on the strength of his physical tools and his surprising raw power for a player his size, but that power didn’t really manifest itself in the minor leagues. In 138 games in Double-A, he slugged .397. In 201 games in Triple-A, he slugged .424, and he only hit 14 home runs. The rest of his game was good enough that the power didn’t have to come to be a valuable contributor, but it was not always obvious that McCutchen was going to turn into what he is today.

But they stuck with him, and perhaps more importantly, they didn’t rush him. The Pirates gave McCutchen 2,200 minor league plate appearances over five seasons before he made his big league debut. They decided not to repeat the mistakes of the organization’s past, when they had aggressively pushed talented but raw youngsters like Jose Guillen and Aramis Ramirez and ended up punting them before watching them develop elsewhere.

Since getting to the big leagues, McCutchen has developed from a very good player into a true superstar, and he should walk away with the league MVP trophy at the season’s end. But this was a process eight years in the making, and McCutchen has more than rewarded the organization’s faith in his abilities. The Pirates had not always been this patient with young talents. Trusting in McCutchen’s skills, even if they weren’t always translating into present results, has paid off in the form of an elite franchise player.

3. They ignored positional sterotypes.

Neil Walker is 6’3, and came up through the minors as a catcher. When it became apparent that he probably wasn’t a big league catcher, they moved him to third base, because that’s where bigger guys with arm strength tend to play. In 2010, someone in the organization decided that it would be worth experimenting with him as a second baseman, even though he didn’t look anything like a second baseman, and the tools profile suggested that his arm would be mostly wasted at the position.

With a lot of hard work, the Pirates have helped turn Walker into a solid enough defender at the position, and his bat provides a lot of value at an up the middle spot where most teams aren’t getting his kind of offensive production.

In left field, they went the other direction entirely. Despite posting just a .300 on base percentage and hitting nearly three of every five balls in play on the ground in his debut last season, Starling Marte was handed the starting left field job out of spring training this year. The Pirates knew that Marte wasn’t going to be a big home run guy, and he doesn’t fit the typical left field profile at all. He’s a center fielder playing left because the Pirates already have McCutchen.

But instead of buying into the notion of needing power from the corners and defense up the middle, the Pirates just found a way to put their most talented players on the field, and if that meant playing a speed-and-defense center fielder in left, then so be it. Marte has responded with a breakout season, providing remarkable value with his legs on both offense and defense. Rather than thinking his speed would be wasted in a corner spot, the Pirates gave Marte a chance to show what he could do, and he’s been one of the NL’s best left fielders this season.

The idea that players at certain positions need to have a particular offensive skillset is almost entirely outdated, and the Pirates have done well to ignore those norms, putting players at positions where they might not look like the part and getting significant value in the process.

4. They bought into the value of defensive shifts.

I don’t have much to add about this that wasn’t already covered in Travis Sawchick’s terrific profile on the team’s defense last week, so go read that piece if you haven’t already. The long and short of it is that the Pirates have become one of the most aggressive shifting teams in the majors, and have attempted to use every resource available to allow as few hits as possible to their opponents.

This is one of the best examples of collaboration between old school and new school ideas that baseball has seen. Clint Hurdle is not a young guy fresh out of an Ivy League school. The Pirates didn’t fire all their scouts and player development guys and replace them with computers. The coaching staff bought in to what the front office was selling, and the team as a whole has benefited from the collaboration. This is how this is supposed to work. It isn’t Michael Lewis’ characterization of the war between the smart and the dumb, it’s combining the perspectives and information into the best plan possible. The Pirates and their defense are a fantastic example of what can happen when everyone is on the same page.

5. They saw value in Russell Martin.

I’m saving this one until last, but it really could be #1, honestly. If it weren’t for McCutchen’s presence on the same Pirates team, I think you could actually put together a compelling case for Russell Martin as the 2013 NL MVP.

Yeah, I know, that sounds kind of ridiculous given his .230/.329/.384 batting line, but Martin has been a defensive monster this season, and it’s gone mostly unnoticed. It shouldn’t, though. He’s had one of the best defensive seasons from a catcher in recent history.

Let’s start with the stuff that’s easy to quantify. Martin leads the majors in gunning down runners, having created 36 outs for the team by nailing opposing base stealers, a 40% caught stealing rate. That CS%, in and of itself, isn’t anything unheard of, but most guys who are as good at throwing runners out as Martin is don’t get run on very often. Whether it is because of lingering reports on how bad the Pirates were at throwing runners out last year or simply Martin not appearing to have as strong an arm as some other catchers, runners have been testing him in almost every game he’s caught, and he’s created more than a full game’s worth of outs in the process.

And while throwing out runners is generally dependent on work from both the pitchers and the catchers, it’s hard to argue that Martin’s success has been due to the pitching staff he has worked with when you see the awful success rate the non-Martin Pirates catchers have had at throwing runners out this year. Between them, Michael McKenry, John Buck, and Tony Sanchez have allowed 40 stolen bases and thrown out just seven attempted stealers, a lousy 15% caught stealing rate that is in line with what the Pirates as a team gave up last year.

Based on the DRS calculations, Martin has saved the Pirates nine runs through base stealing prevention, adding basically a win of value just by gunning down opposing runners so often. And that’s just one part of catcher defense. Martin has also been terrific at the others parts as well.

One of the stats we have here on the site but we don’t talk about much is RPP, which is runs saved or lost due to passed pitches, or said more commonly, blocking balls in the dirt. Based on the location of the pitches he’s received, the expectation is that Martin would have had 65 pitches get by him for wild pitches or passed balls; in reality, he’s only had 54 get by him, a difference of +11 pitches blocked, which translates into four runs saved. The #1 catcher in pitch blocking, Yadier Molina, is at +5.5 runs, so Martin isn’t far off the big league lead in this area either.

And then there’s pitch framing. Jeff Sullivan has written about Martin’s framing abilities on multiple occasions, noting even early in the season that Martin’s receiving skills could have a significant positive impact on his team’s pitchers. While pitch framing calculations are still in their early stages, Matthew Carruth’s catcher report at StatCorner estimates that Martin has saved the Pirates 18 runs through turning balls into strikes, the fourth highest total in baseball.

We’re not at a point where we can say that the calculations are perfectly capturing the entirety of a backstop’s influence on his pitching staff, but as we noted earlier, the Pirates have gotten some pretty surprising performances from discarded pitchers, and it logically follows that Martin has had a hand in their resurgence. Even if you only give him partial credit for the framing runs saved, this is still an area where he has added real value.

Even without framing value, our estimate of runs saved by a catcher’s defensive performance rates Martin’s 2013 season as the most valuable since 2002, the first year we have play by play data. If you give him some boost for his framing skills, it’s not a significant leap to say that Martin has been as valuable a defender as anyone else in baseball this year, Manny Machado and Andrelton Simmons included.

Martin probably won’t appear on very many MVP ballots, but he is one of the main reasons the 2013 Pirates are an excellent baseball team. While the general consensus has acclaimed Francisco Liriano as the best free agent bargain of the winter, I’d give that crown to Martin. The fact that the two best candidates are both on the Pirates says something about just how good an off-season Pittsburgh had last year.

This Pirates team isn’t the fruit of 21 years of losing. They aren’t just riding the wave of years of high draft picks. This team was built intelligently with undervalued assets and pieces that fit together perfectly. The A’s are probably always going to be the model franchise for what a smart team can do with limited resources, but let’s not overlook how the Pirates built a winner after two decades of losing. This is a shining example of a well constructed team, and they deserve all the success they’ve gotten.

Congratulations to the long suffering Pirates fans who will get to see their team play in the postseason this year, and congratulations to the people responsible for building the team that made it possible.