As the 2017 regular season started to hit the homestretch, it became very clear the Houston Astros and Los Angeles Dodgers were postseason bound. On July 31, the Astros had a 16-game lead in the American League West, while the Dodgers had a comfortable cushion of 14 games in the National League West.
Both teams, though, felt they could use a rotation upgrade to increase their chances of playing deep into October. The Dodgers made their move right at the edge of the non-waiver Trade Deadline on July 31 by acquiring Yu Darvish from the Texas Rangers. The Astros waited a full month to make their move, nabbing Justin Verlander on Aug. 31 after the Tigers had put the veteran right-hander on waivers.
• Gear up for the World Series:Astros | Dodgers
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Both moves, obviously, have paid large dividends for the two clubs preparing to play tonight in Game 1 of the World Series presented by YouTube TV. Darvish was solid in August and September (4-3 with a 3.44 ERA in nine starts) and has won both of his postseason outings (11 1/3 IP, 8 hits, 2 ER, 1 BB, 14 K).
"We went into July with the mindset of focusing on impact-type talent," said Andrew Friedman, the Dodgers' president of baseball operations, at the beginning of October. "To the extent we were able to line up on it, we would be aggressive in doing that. Our most acute need was left-handed relief, but if there was someone who could impact us in October … and Yu fits that perfectly."
Verlander has been other-worldly, with his September (5-0, 1.06 ERA in five starts) just a tune-up to his postseason run, particularly in his AL Championship Series MVP-winning peformance (postseason combined 4-0 in 24 2/3 IP, 17 H, 4 ER, 6 BB, 24 K).
"The Verlander deal took a long time to pull together, and it wasn't clear it would come together," Astros general manager Jeff Luhnow said as the postseason was about to begin. "To get two years of control, along with him pitching as well as he has pitched in his career, we went through a pretty disciplined approach to get that result."
That Los Angeles and Houston would get such production from trades should come as no surprise. The Dodgers had more players on their roster at the start of the postseason acquired via trade or waivers (14) than any team in the playoffs. The Astros, with 11, weren't too far behind. Tweaks to the World Series roster brought the Dodgers down to 13, with Curtis Granderson likely making way for Corey Seager, but it's still the top total. That baker's dozen produced a bWAR (Baseball-Reference WAR) of 21.1 for the Dodgers in 2017. Houston now has an even dozen on the roster, which put up a bWAR of 17.8.
• How they were built:Astros | Dodgers

As much as trades have been crucial parts of building these World Series participants, there have been some big contributions from homegrown players. L.A. is obviously thrilled to get Seager back after he missed the NLCS presented by Camping World with a back issue, joining Clayton Kershaw and Cody Bellinger as Dodgers draftees making an impact. The Dodgers' homegrown players put up a bWAR of 21.6.
The Astros have eight homegrown players on their World Series roster, and like the Dodgers, have a pair of infielders (Houston's entire starting infield is homegrown, actually) and a frontline starter who originally signed with the organization leading the group. Carlos Correa was the No. 1 overall pick in 2012, and he hit .333 and slugged .556 in the ALCS presented by Camping World. International signee Jose Altuve has gone 16-for-40 (.400) this postseason, with five homers and eight RBIs. Dallas Keuchel, a humble seventh-round pick back in 2009, may have been overshadowed by Verlander this postseason, but he has a combined 2.60 ERA in 17 1/3 playoff innings this October, having allowed just 14 hits and five walks while striking out 25. In total, the eight homegrown players provided 28.8 in bWAR.
Houston has been more "active" on the free-agent market than Los Angeles, though that's all relative. There are five free agents on the Astros' current roster, with Josh Reddick leading the way in terms of regular-season bWAR (4.4), though he's gone just 7-for-41 in the postseason. The Dodgers, for their part, have four free agents for 7.6 bWAR. Justin Turner's 5.7 mark was tops during the season, and he's gone 6-for-18 with a pair of homers this postseason.