The Houston Astros and Boston Red Sox will meet in the 2021 American League Championship Series in a matchup that seemed highly unlikely at the start of the MLB season. The odds have been against Boston, in particular, for much of the year, and that remains the case heading into the ALCS.

The Red Sox are +132 underdogs in the upcoming series, according to FanDuel Sportsbook. The Astros are -156 favorites to reach this year’s Fall Classic.

Houston is playing in its fifth straight ALCS after trips to the World Series in 2017 and 2019. Boston is back in the playoffs for the first time since winning the 2018 title.

Both teams won their respective division series in four games. As the AL’s No. 2 seed, the Astros were favored to eliminate the Chicago White Sox. The Red Sox, however, were decided underdogs against the top-seeded Tampa Bay Rays. Boston beat the New York Yankees in the AL Wild-Card Game in order to clinch a spot in the ALDS.

Houston is the better team by just about every measure. The Astros finished three games ahead of the Red Sox in the standings. Houston went 5-2 against Boston in the regular season, outscoring the Red Sox 42-25 in those matchups.

Offense is Boston’s strength, but it was Houston that led the majors in runs scored over 162 games. The Red Sox had an average pitching staff, while the Astros were fourth in the AL with a 3.76 ERA. 

In the postseason, Boston’s lineup has been red hot. Even after being shut out in their series opener with the Rays, the Red Sox are hitting .328/.372/.547 to lead all playoff teams. Boston is first with 11 postseason home runs, giving them seven more than Houston. 

Alex Verdugo, Kike Hernandez and Rafael Devers all drove in six runs apiece in the ALDS. J.D. Martinez picked up seven hits in 15 at-bats. 

The Astros’ offense has continued to rake in October, scoring 31 runs in four games. Houston scored at least six runs in each ALDS game and outscored Chicago by at least five runs in all three of their victories. 

Jose Altuve has established himself as one of the great postseason hitters in MLB history. After hitting .313/.476/.625 against Chicago, the second baseman has 19 home runs and a .953 OPS in 67 playoff games. Michael Brantley hit .368 in the ALDS after finishing just behind teammate Yuli Gurriel in the race for the AL batting title.

The starting rotation might be where Houston’s greatest advantage lies. Lance McCullers Jr. is the best starter in the series. After taking the hill twice this postseason, McCullers has a 2.83 ERA in 57.1 career playoff innings. Framber Valdez and Luis Garcia were above-average starters in the regular season before subpar outings in the ALDS.

Nathan Eovaldi has emerged as Boston’s one true reliable starter. Chris Sale has just one quality start since returning from injury in August and was limited to one inning in his lone ALDS start. Eduardo Rodriguez had a 4.74 ERA in the regular season before giving up four runs in 6.2 innings across two starts last series. 

When Houston and Boston met in the 2018 ALCS, the Red Sox needed only five games to eliminate the Astros before winning the World Series. This year’s matchup should be much more competitive.

With home-field advantage, a better rotation and MLB’s top lineup, Houston has the best chance of winning another AL pennant.

Series Prediction: Houston in six

ALCS Schedule (start times after Game 1 are TBD)

Game 1: Friday, Oct. 15, Red Sox at Astros, 8:07 p.m. ET (FOX)

Game 2: Saturday, Oct. 16, Red Sox at Astros, TBA (FOX or FS1)

Game 3: Monday, Oct. 18, Astros at Red Sox, TBA (FS1)

Game 4: Tuesday, Oct. 19, Astros at Red Sox, TBA (FS1)

Game 5: Wednesday, Oct. 20, Astros at Red Sox, TBA* (FS1)

Game 6: Friday, Oct. 22, Red Sox at Astros, TBA* (FS1)

Game 7: Saturday, Oct. 23, Red Sox at Astros, TBA* (FOX or FS1)

*If necessary

Alex Bregman Jose Altuve Astros Alex Bregman #2 and Jose Altuve #27 of the Houston Astros celebrate their team's win over the Boston Red Sox in Game One of the American League Championship Series at Fenway Park on October 13, 2018 in Boston, Massachusetts. Photo: Elsa/Getty Images