Roberto Osuna could be the squeaky wheel for the otherwise-excellent Astros. (Morry Gash/Associated Press)

Baseball’s playoff teams have shown the strengths that got them to October. It’s now time to expose each squad’s fatal flaw, the glaring weakness that could end its World Series bid.

Whether it’s a key injury, a hole in the lineup, a struggling starting pitcher or a shaky bullpen, here are the most notable flaws for all of the contenders:

Houston Astros

  • Odds of winning the World Series: 32 percent (per FanGraphs)
  • Fatal flaw: Closer

The Astros are the best-hitting team in the majors (batting .274 with an .848 on-base-plus-slugging percentage, creating runs at a rate that is 25 percent higher than average after accounting for league and park effects) and also boast a solid pitching staff (major league-leading 28 percent strikeout rate with the second-lowest ERA), making a fatal flaw tough to find. But their closer, Roberto Osuna, has been shaky at times.

July was Osuna’s worst month, a span in which line drives against him were more frequent (30 percent of batted balls in play) and his command wasn’t up to par (walking a season-high 9 percent of batters faced). He started to settle down, but his ERA ballooned to 5.00 over nine innings in August, causing some concern over which pitcher we will see in the playoffs.

New York Yankees

  • Odds of winning the World Series: 17 percent
  • Fatal flaw: The rotation

The Yankees’ starting rotation has allowed 12 more runs than expected after taking into account how many outs were left in the inning and how many men were on base at the time of each pitch. That’s the worst performance among American League playoff teams, with New York being the only one of the five with a negative number.

Teams with below-average rotations have been able to win championships, but the Yankees also are lined up to have a starter, James Paxton, make his first career postseason start. Since 2006, 129 pitchers have made their postseason debut, but less than half (63) turned in a quality start (six or more innings with three or fewer earned runs).

Los Angeles Dodgers

  • Odds of winning the World Series: 17 percent
  • Fatal flaw: Closer

Kenley Jansen hasn’t been reliable, and he called his 2019 campaign the most frustrating of his career. The closer had a career-worst 3.77 ERA and issued 2.3 walks per nine innings, his worst mark since 2014. His strikeout rate rebounded a little from last season but remains several percentage points lower than when he was at his peak, a concerning trend for a closer.

Atlanta Braves

  • Odds of winning the World Series: 8 percent
  • Fatal flaw: Dependency on luck

It’s possible the Braves are more lucky than good.

Their plus-112 run differential was more in line with a team that wins 92 games, not 97. And if we take into account the sequence of their plate appearances — four walks in a row result in a run, but spread those walks out over four innings and the impact could be negligible — they should have had 90 wins.

Why was Atlanta able to outperform expectations by such a wide margin? It was 28-16 in one-run games and 11-6 in games that needed extra innings. Luck like that has a tendency to even out at the worst possible time. Last year’s champions, the Boston Red Sox, went 8-5 in extra-inning games. In 2017, the Astros went 19-13 in one-run games and 4-4 in extra innings.

Minnesota Twins

  • Odds of winning the World Series: 7 percent
  • Fatal flaw: Reliance on home runs

The Twins hit 307 home runs. Nelson Cruz led the way with 41, and four others (Max Kepler, Miguel Sanó, Eddie Rosario and Mitch Garver) had 30 or more. Since 2006, no team has had more batters with 30 or more home runs in a season. Unfortunately, relying on the long ball, even to a historic degree, doesn’t guarantee the ultimate postseason prize. Only one team over the past 13 years has led the majors in home runs and won the World Series: the 2009 Yankees.

Year Team Playoff result
2006 Chicago White Sox Did not qualify
2007 Milwaukee Brewers Did not qualify
2008 Chicago White Sox Lost ALDS
2009 New York Yankees Won World Series
2010 Toronto Blue Jays Did not qualify
2011 New York Yankees Lost ALDS
2012 New York Yankees Lost ALCS
2013 Baltimore Orioles Did not qualify
2014 Baltimore Orioles Lost ALCS
2015 Toronto Blue Jays Lost ALCS
2016 Baltimore Orioles Lost AL wild-card game
2017 New York Yankees Lost ALCS
2018 New York Yankees Lost ALDS

Tampa Bay Rays

  • Odds of winning the World Series: 6 percent
  • Fatal flaw: Hitting

The Rays had one of baseball’s best pitching staffs, but their batters could struggle in the postseason. Tampa Bay created runs at a rate that was just 3 percent higher than average after accounting for league and park effects. The Rays also struggle against high-end fastballs: The club batted .223 with a .370 slugging percentage against fastballs at 95 mph or higher this season. (The league average was .250 with .421 slugging.) Pitching staffs featuring the highest rate of fastballs at 95 mph or higher include American League contenders such as the Astros (second-most, 20 percent), Yankees (seventh-most, 17 percent) and Athletics (11th, 14 percent). Two of Tampa Bay’s worst on-base-plus-slugging performances came against the Yankees (.677) and Astros (.662).

Washington Nationals

  • Odds of winning the World Series: 5 percent
  • Fatal flaw: Bullpen

The Nationals’ bullpen was one of baseball’s worst. Their relievers allowed 94 more runs than expected after taking into account the outs remaining in the inning and the men on base during each at-bat (only the tanking Baltimore Orioles were worse), and they stranded a major league-low 67 percent of runners on base.

Their most reliable reliever, Sean Doolittle, allowed 12 earned runs in 15 innings (a 7.20 ERA) since the start of August. Eight of the 50 balls put in play against him in August and September were hit on the sweet spot of the bat, also known as a barrel. Doolittle allowed seven barrels on 127 balls put in play from March to July. Batters have been hitting the ball harder off him each month since June.

St. Louis Cardinals

  • Odds of winning the World Series: 4 percent
  • Fatal flaw: Hitting

The Cardinals were a below-average hitting team, creating runs at a rate that was 5 percent lower than average after taking into account league and park effects. Some of the blame could be placed on first baseman Paul Goldschmidt, the team’s top offseason acquisition. His OPS (.821) was his lowest output since his rookie year of 2011 (.808), and both his walk rate and strikeout rate worsened.

The pitches giving him the most trouble are change-ups and splitters. He batted just .188 against those with 23 strikeouts over 85 at-bats ending on an off-speed pitch. Atlanta’s Dallas Keuchel loves throwing change-ups to right-handed batters such as Goldschmidt; he used the pitch to hold right-handed batters to a .218 average against with 13 strikeouts over 55 at-bats. It’s sometimes unfair to say one batter can make the difference between victory and defeat, but consider Goldschmidt batted .302 with 26 home runs and a .967 OPS in 392 plate appearances during Cardinals wins and .205 with eight home runs and a .629 OPS in 290 plate appearances in losses.

Oakland Athletics

  • Odds of winning the World Series: 3 percent
  • Fatal flaw: Reliance on home runs

This isn’t one of the “Moneyball” clubs of the early 2000s — Oakland digs the long ball. Seven of its players hit more than 20 home runs, and the team’s on-base percentage was only 1 percent higher than the league average.

That could be a challenge against the Tampa Bay and Houston rotations. The Rays’ starters allowed the fewest home runs per nine innings (1.0) and were adept at keeping the ball on the ground (league-high 45 percent groundball rate). The Astros’ starters produced a groundball rate of 44 percent.

Milwaukee Brewers

  • Odds of winning the World Series: 1 percent
  • Fatal flaw: Rotation

The Brewers were the hottest team in September, their 20-7 record the best in the majors. Yet they still have pitching concerns. Their starters produced just 34 quality starts, the second fewest after the Los Angeles Angels (22). The fewest regular season quality starts by a World Series winner was 65 by the 1981 Dodgers.

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