Despite the presence of MVP candidate Mookie Betts, among others, the Red Sox are not locks to win it all. (Julio Cortez/Associated Press)

The Boston Red Sox won 108 games in 2018, the most in franchise history and just the fourth time a Red Sox team won 100 or more games in their 117-year history.

Mookie Betts, one of the front-runners for AL MVP, hit 32 home runs and stole 30 bases, becoming only the second 30-30 player in franchise history (Jacoby Ellsbury in 2011). Teammate J.D. Martinez hit .330 with 43 home runs and 130 RBI during his first season in Boston; he, too, will get MVP consideration. Ace Chris Sale would have the highest single-season strikeout rate (38.4 percent) by a starting pitcher in MLB history if he qualified for the ERA title — he’s about nine innings short — edging out a former Red Sox pitcher, Pedro Martinez (37.5 percent in 1999), for the honor. Rick Porcello and David Price join Sale to create the fifth-best starting rotation in the majors this season.

Yes, that’s absolutely a star-studded lineup. So why do we — in addition to FanGraphs and FiveThirtyEight — give the Houston Astros and Los Angeles Dodgers a better chance to win the 2018 World Series?

Chances to win 2018 World Series (none/The Washington Post)

History is one explanation. Since 1969, only 12 teams have recorded baseball’s best record and gone on to win a championship that season. Plus, Boston got a little lucky during the regular season. For example, based on runs scored and allowed (Pythagorean wins), we would expect a team with a plus-229 run differential to win 104 games, four fewer than the team’s actual record. If we take into account the sequence of each at-bat, also known as baseruns, the expected record drops even further to 99-63, nine wins fewer than Boston earned in 2018. Here’s why the sequence of at-bats are important: If a team draws four walks in a row, that results in a run, yet if those same four walks are spread out over four different innings the impact, unless it occurs in a bases loaded situation, would be a lot less.

The Dodgers, by comparison, won a league-leading 10 fewer games than expected based on runs scored and allowed and nine games fewer per baseruns. The Astros won six fewer games per runs scored and allowed and had the record you’d expect based on the sequencing of their at-bats.

Actual vs. expected win in 2018

Looked at another way, the Red Sox would be expected to beat the Astros 51 percent of the time at Fenway Park, their home field. Not exactly the edge we would expect from the best team in baseball. The Red Sox would be more likely to beat the Dodgers at home, but only by two percentage points (53 percent).

In addition, the Dodgers and Astros have a more talented roster on a position by position basis per FanGraphs version of wins above replacement. Boston has a clear edge from its left fielders, right fielders and at DH, but yielded the top spot to either Houston or Los Angeles in other areas. Overall, Boston is third in total fWAR in comparison to the other two contenders, albeit by a less-than-significant margin. In other words, the Red Sox are better in the win-loss column but not in regards to talent.

fWAR by position in 2018. Green indicates the top figure, red is the worst figure in the group.

And that makes the Dodgers the better future bet. The Westgate SuperBook has set the Red Sox as 3-to-1 favorites, with the Astros (7-to-2 odds) and Dodgers (5-to-1) close behind. According to our calculations, the Dodgers are an underlay, meaning their odds are higher than they should be.

Team Chance to win World Series WashPost odds Westgate odds
Dodgers 22% 7-to-2 5-to-1
Astros 21% 4-to-1 7-to-2
Red Sox 18% 5-to-1 3-to-1

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