How they were built: Oakland A's

In the 10 years that have passed since "Moneyball," Michael Lewis' seminal book about the 2002 A's, was published, it might not appear as if much has changed in Oakland. Billy Beane is still the general manager and his quest to find undervalued players continues.

Some things, however, have changed. The A's have seen their payroll increase about $20 million in the past decade as they have invested more heavily for free agents such as Yoenis Cespedes, Coco Crisp and Bartolo Colon.

A's owner Lew Wolff recently told MLB.com that he views this year's team much differently than the 2002 and '03 clubs that also won the American League West.

"We've always wanted to be competitive, so this is not what 'Moneyball' is supposed to look like," Wolff said. "We're not the bottom of the salary list. Strategically, we make investments where Billy and his guys think we need them.

"We're not paupers by a long shot."

Although the A's might not have to be as frugal as they were a decade ago, they still have been careful to build the team around young, controllable talent, such as Jarrod Parker, Josh Donaldson and Josh Reddick.

Most of those players came to Oakland after the 2011 season through a series of trades and free-agent signings that overhauled the roster. Older players gave way to a younger nucleus that quickly became one of the more formidable teams in the AL and made a late charge to the division title.

For Wolff, it was a season ahead of schedule. He said when the A's made those moves, they were targeting 2013, not '12. But the plan paid off a year early, and the A's have now won back-to-back division titles for the first time since the Moneyball era. They begin the best-of-five AL Division Series against the Tigers in Oakland on Friday night at 6:30 p.m. PT on TBS.

"We were building up a team. I didn't think it would come along as fast as it did," Wolff said. "I think the progression of what we've done, giving up certain players and getting others, the movement of players every day, is brilliant."

Here's a closer look at how the A's roster was built:

Homegrown players

Most of the players on the A's playoff roster began their professional careers with another organization. But Oakland's handful of homegrown players has played a key role this season, led by Cespedes.

The A's surprised the industry by signing Cespedes, a Cuban native, to a four-year, $36 million deal in February 2012. Since then, all he has done is win the '13 Home Run Derby and help the A's to back-to-back division titles.

The A's starting rotation includes three recent Draft picks in Dan Straily, Sonny Gray and A.J. Griffin, though Griffin was left off the ALDS roster due to elbow tendinitis. Straily and Griffin were later-round picks but have transformed themselves into key pieces of Oakland's staff. Though Gray was the team's first-round selection in 2011, he has had to prove himself. His undersized stature made some teams view him as a future reliever, but the A's saw Gray as a starter, and he has not disappointed. He made his Major League debut in July and has a 2.85 ERA in 10 starts.

Trades

Beane's greatest tool in defining the A's direction in the last few years has been the trade. He acquired 17 members of the ALDS roster in 15 different moves, dating back to the trade that brought Daric Barton (along with Dan Haren and Kiko Calero) to Oakland in exchange for Mark Mulder in 2004.

While the trades that shaped this year's team have taken place gradually since that first move, December 2011 would see three of Beane's most important deals. Two months after the A's finished a 74-88 campaign that placed theim third in the AL West, Beane made a series of trades that changed the course of the franchise.

First, Beane shipped Trevor Cahill and Craig Breslow to the D-backs. Two weeks later, he sent Gio Gonzalez to the Nationals, and two days after that, he traded Andrew Bailey and Ryan Sweeney to the Red Sox. In return, the A's got 10 players, including Parker, Ryan Cook, Tommy Milone, Derek Norris and Reddick.

Wolff said the A's determined they needed to get younger at certain positions and moved aggressively to make it happen that winter.

"You have to always give up something to get something in this business," Wolff said. "And that was a strategic move, very, very vigorously determined by Billy and his people."

The deals didn't stop, however. Seven more members of the Division Series roster were acquired since December 2011. Most recently, Beane traded Grant Green, then the A's No. 3 prospect, to the Angels for Alberto Callaspo at the Trade Deadline.

Free agents

While Oakland has mostly looked to other markets to build their roster, they have plucked a few important players from free agency. The A's signed Colon to one-year deals in each of the past two years, and he rewarded them by pitching his way into the AL Cy Young Award conversation this season.

Colon hasn't been the only player in recent years to experience a revitalization in Oakland. Crisp was coming off the worst season of his career when he signed a one-year, $5.25 million deal with the A's in 2009. Grant Balfour was a good reliever when he came to Oakland in '11, but he made his first All-Star team this year as he developed into one of the most dependable closers in the AL.

Perhaps most remarkable of all has been Brandon Moss. He signed a Minor League free-agent deal in 2011 after struggling to stick in the Major Leagues with three different clubs from 2007-11. Since coming to Oakland, he has hit 51 home runs, which leads the A's over that span.