The Giants, Dodgers and Rays all won 100 games or more in 2021, with San Francisco and Tampa Bay finishing with the best record in the National and American Leagues, respectively. Each organization has built a winner in different ways.

The Giants were the best team in baseball this year thanks in large part to the 12 free agents on their Division Series roster, the largest number among the 10 playoff teams, led by Kevin Gausman and his 5.0 Wins Above Replacement. The Dodgers, who have typically been one of the most homegrown playoff teams in recent years, are actually more balanced in 2021, with 10 homegrown players, 10 acquired via trade or waivers and six free agents. The Rays, for their part, have leaned hard on the trade market, with 19 of their 26-man roster coming by way of a deal -- by far the most of any postseason team.

• Complete 2021 postseason schedule

Below is a detailed breakdown of how each of the postseason teams was built. Note that if a player was acquired by a team, went to another team and then returned to the original team, he is listed according to how he was most recently acquired. If a player was acquired by a team then re-signed as a free agent without going to another team, he is listed according to how he was originally acquired. The Cardinals' and Yankees' numbers are based on their projected Division Series rosters.

American League

RAYS (45.6 WAR, 7th among 10 teams)

Homegrown: 5 (12.6 WAR)
• Draft: 4 (9.1 WAR)
• International: 1 (3.5 WAR)
Free agents: 2 (1.7 WAR)
Trades: 19 (31.3 WAR)

Tampa Bay followed up its 2020 World Series run with its first 100-win season in franchise history. There has been plenty of ink spilled about the organization’s farm system in recent years, and that bore fruit in 2021 in the form of Wander Franco and Shane McClanahan playing big roles as rookies. Even 2015 third-rounder Brandon Lowe, who was never a Top 100 prospect himself, was arguably the club’s MVP this season with 39 homers, and 2010 10th rounder Kevin Kiermaier brought his trademark defense up the middle. But where this version of the AL East champs benefited most was on the trade market. The Rays have become famous (or infamous) for dealing popular homegrown talents as they get deeper into arbitration. But the organization’s trade of Chris Archer brought in expected postseason contributors Austin Meadows and Shane Baz (as well as the injured Tyler Glasnow), and Blake Snell’s move to San Diego netted Francisco Mejia and Luis Patiño. The Rays’ trade success goes both ways too. The organization struck gold when it picked up Randy Arozarena from the Cardinals in January 2020, and the acquisition of Joey Wendle -- in what looked like a minor move in December 2017 -- continues to pay dividends. On a much bigger note, the club hopes the arrival of Nelson Cruz, who cost two solid prospects at this year’s Deadline, helps push the team over the edge.

WHITE SOX (53.1 WAR, 3rd among 10 teams)

Homegrown: 11 (19.3 WAR)
• Draft: 9 (12.7 WAR)
• International: 2 (6.6 WAR)
Free agents: 3 (6.6 WAR)
Trades: 11 (26.1 WAR)
Waivers: 1 (1.1 WAR)

The White Sox assembled back-to-back playoff teams for the first time largely via trades. They turned Adam Eaton into Lucas Giolito (and Dane Dunning, whom they dealt for Lance Lynn), Chris Sale into Yoán Moncada and Michael Kopech and José Quintana into Dylan Cease and Eloy Jiménez. They've invested heavily in international signings and have no regrets about landing Cuban defectors Luis Robert and José Abreu on original deals that cost a combined $119 million. First-round picks Carlos Rodón, Tim Anderson, Garrett Crochet and Andrew Vaughn also have paid off, as have free-agent signees Yasmani Grandal and Liam Hendriks.

ASTROS (52.8 WAR, 4th among 10 teams)

Homegrown: 13 (38.5 WAR)
• Draft: 7 (21.8 WAR)
• International: 6 (16.7 WAR)
Free agents: 4 (4.3 WAR)
Trades: 9 (10.0 WAR)

The Astros have nearly twice as much homegrown WAR as any other playoff team and lead all postseason clubs in production from both draftees and international signings. Their two best players this year are former top-five-overall picks Carlos Correa and Kyle Tucker, and another (Alex Bregman) might have outshone them if he hadn't missed two months with a quadriceps injury. Supplemental first-rounder Lance McCullers has been their best pitcher, while late-rounders Chas McCormick (21st round) and Jake Meyers (13th) have filled a need in the outfield. Houston has found a number of international bargains, including Jose Altuve ($15,000), potential AL Rookie of the Year Luis Garcia ($20,000), Framber Valdez ($10,000), José Urquidy ($100,000) and Cristian Javier ($10,000). A five-year, $47.5 million contract to sign Yuli Gurriel also has paid off handsomely, while their best import is fellow Cuban defector Yordan Alvarez, pilfered from the Dodgers in a 2016 trade for Josh Fields. Though Houston hasn't delved much into the free-agent market, Michael Brantley has worked out well.

YANKEES (47.8 WAR, 6th among 10 teams)

Homegrown: 6 (11.9 WAR)
• Draft: 5 (11.2 WAR)
• International: 1 (0.7 WAR)
Free agents: 7 (16.1 WAR)
Trades: 13 (19.8 WAR)

The Yankees relied on free agents more heavily than any postseason team except for the Giants, though surprisingly Jonathan Loáisiga and Nestor Cortes (both brought in on Minor League deals) rank as their next most productive signees this season behind $324 million man Gerrit Cole. They’ve also used their farm system depth to pull off key trades for the likes of Joey Gallo, Giancarlo Stanton, Chad Green, Jameson Taillon and Anthony Rizzo. Draftees Aaron Judge and Jordan Montgomery are the only homegrown players to rank among the 15 best in terms of bWAR on New York's roster, while Gary Sánchez is the lone international signee.

RED SOX (44.4 WAR, 8th among 10 teams)

Homegrown: 6 (12.4 WAR)
• Draft: 4 (4.0 WAR)
• International: 2 (8.4 WAR)
Free agents: 7 (10.9 WAR)
Trades: 10 (17.3 WAR)
Rule 5: 1 (2.9 WAR)
Waivers: 2 (0.9 WAR)

On the homegrown front, the Red Sox have two international All-Stars in Xander Bogaerts and Rafael Devers but received fewer contributions from draftees (led by Tanner Houck and Christian Vázquez) than any playoff team. They've built their club with a little bit of everything, including free agents (Kiké Hernández, J.D. Martinez and Hunter Renfroe) and trades (Nathan Eovaldi, Kyle Schwarber, Nick Pivetta and Alex Verdugo). Boston has done a nice job in the bargain bin, grabbing a key Rule 5 pick last December (Garrett Whitlock, from the rival Yankees no less) and a pair of useful waiver pickups (Christian Arroyo, Travis Shaw).

National League

BRAVES (41.7 WAR, 9th of 10 teams)

Homegrown: 8 (16.4 WAR)
• Draft: 5 (13.6 WAR)
• International: 3 (2.8 WAR)
Free agents: 9 (9.5 WAR)
Trades: 8 (15.5 WAR)
Waivers: 1 (0.3 WAR)

The Braves’ homegrown total, in terms of WAR, certainly took a hit with the season-ending injuries to Ronald Acuña Jr. and Mike Soroka, but there was a core this year of draftees who picked up the slack. Freddie Freeman, Austin Riley and Ian Anderson combined for 13.4 of that group’s 16.4 WAR, while Ozzie Albies led the international signees with 3.5 WAR, the only positive figure among the international players on this roster. Trades, once again, have played a large role in forming this playoff team, from those acquired as a prospect, like Max Fried and his pitching-staff leading 5.4 WAR, to newcomers this year like Eddie Rosario. The free agent acquisition of Charlie Morton may have been one of the biggest ones of any playoff team as he helped anchor the Soroka-less rotation, along with Fried, and amassed a 4.0 WAR this year.

BREWERS (48.6 WAR, 5th among 10 teams)

Homegrown: 4 (13.2 WAR)
• Draft: 4 (12.7 WAR)
Free agents: 8 (10.4 WAR)
Trades: 13 (25.7 WAR)
Waivers: 1 (-0.2 WAR)

On the face, it might look like a limited homegrown contribution level from the NL Central champs. Only five players on the club’s expected NLDS roster fit the description, all via the Draft. But look at that names contained therein. Corbin Burnes (2016, fourth round) and Brandon Woodruff (2014, 11th) were major drivers of Milwaukee’s success, which relied on quality pitching and defense. The addition of Willy Adames via midseason trade was a major boon for the offense, and similarly, Eduardo Escobar helped out on the infield after a Deadline deal. It may be easier to forget that Freddy Peralta and Josh Hader were actually trade acquisitions as well, even though their entire Major League careers have been spent as Brewers, and a November 2019 swap with the Padres that brought over Luis Urias and Eric Lauer looked better than ever in 2021. Milwaukee has been shrewd on the free-agent market in recent years as well by signing Avisaíl García and Kolten Wong over the last two offseasons. Even when franchise cornerstone Christian Yelich has a down year, the Brewers found a way because of the wins they’ve found with moves of a wide variety.

GIANTS (53.5 WAR, 1st among 10 teams)

Homegrown: 8 (20.6 WAR)
• Draft: 6 (19.2 WAR)
• International: 2 (1.4 WAR)
Free agents: 12 (22.4 WAR)
Trades: 5 (8.9 WAR)
Waivers: 1 (1.6 WAR)

The Giants surprisingly led the Majors with a franchise-record 107 victories, and they couldn't have done it without a slew of astute free-agent signings. No postseason roster features more free agents and free-agent production than San Francisco's, highlighted by short-term deals for Kevin Gausman, Anthony DeSclafani and Darin Ruf. The Giants also rank second in bWAR by draftees, led by fourth-rounders Brandon Crawford and Logan Webb, first-rounder Buster Posey, 10th-rounder Tyler Rogers and sixth-rounder Steven Duggar. Kris Bryant was a big-name trade addition this July, but stealing Mike Yastrzemski from the Orioles for righty prospect Tyler Herb in March 2019 was just as important. Jarlin García is the most valuable waiver claimee on any playoff club.

DODGERS (53.4 WAR, 2nd among 10 teams)

Homegrown: 9 (22.1 WAR)
• Draft: 7 (15.4 WAR)
• International: 2 (6.7 WAR)
Free agents: 6 (9.1 WAR)
Trades: 10 (21 WAR)
Waivers: 1 (1.2 WAR)

Though the Dodgers' streak of eight consecutive NL West titles came to an end, they still won 106 games (tying a franchise record) with a team that received above-average production from homegrown players, free agents and trade acquisitions. Their best player this year was Walker Buehler, and they also received significant contributions from fellow first-round picks Corey Seager, Will Smith and Gavin Lux and international signees Julio Urías and Kenley Jansen. The Trea Turner-Max Scherzer trade with the Nationals this July energized the club just like the Mookie Betts deal with the Red Sox did last season. Despite its financial might, Los Angeles has shown a deft touch for low-key free-agent signings such as Justin Turner, A.J. Pollock and Blake Treinen. Their overall playoff roster bWAR total would ffar exceed that of the other playoff clubs if they hadn't lost Max Muncy and Clayton Kershaw in the final week of the season.

CARDINALS (41.2 WAR, 10th among 10 teams)

Homegrown: 14 (20.4 WAR)
• Draft: 11 (15.4 WAR)
• International: 3 (5.0 WAR)
Free agents: 4 (1.0 WAR)
Trades: 8 (19.8 WAR)

The Cardinals have made a habit of playing in October and are participating in the postseason for the third consecutive season. However, this year’s team has a bit of a different feel, having taken an unconventional route to October. It looked as if the Cardinals were going to miss the playoffs, but a red-hot September -- fueled by a 17-game winning streak -- vaulted the team into the Wild Card Game. The bulk of the roster is homegrown with 11 draftees and a trio of international signees. Harrison Bader, Tommy Edman and Dylan Carlson, who began the season as St Louis’ No. 1 prospect, headline the list of homegrown talents. However, the Cardinals have also made big splashes via trades. Paul Goldschmidt and Nolan Arenado are the two obvious big-name acquisitions, but Tyler O’Neill, acquired from the Mariners in 2017, has also been a key contributor and although it’s hard to imagine Adam Wainwright wearing anything but a Cardinals jersey, he also came to the organization via trade (Braves, 2003).