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Astros’ Playoff Roulette

Astros’ Playoff Odds In Flux As Arizona Series Begins...and What Happens If They Advance

MLB: Houston Astros at Seattle Mariners
Astros celebrate winning Sunday’s game against the Mariners.
Steven Bisig-USA TODAY Sports

The Astros’ season is nothing if not exciting. This weekend the Rangers playing the Mariners and the Astros playing the Diamondbacks, and the outcomes of those games will determine whether the Astros get into the playoffs.

Spin the Roulette Wheel

After Thursday night’s wins by the Blue Jays and Mariners, 16 combinations of wins and losses are summarized in the helpful tweet below. At this point, the outcome of remaining Blue Jays’ games has little to no effect on the the Astros’ playoff chances. 11 of the 16 possible outcomes are favorable to the Astros making the playoffs (2 Division; 9 Wild Card).

Fangraphs’ playoff odds model is more sophisticated, but at this stage of the season, the range of results are narrowed. The Astros’ odds of winning the division are small, but the odds of making the playoffs are pretty good at 76%. The Rangers’ are in an extremely good position. The Mariners are clinging more precariously to their playoff hopes, but they can still make it happen by continuing to defeat the Rangers.

Earlier in the season, Baseball Prospectus’ odds for the Astros were much more favorable than Fangraphs’. However, as we approach the end of the season, the Fangraphs and BP models’ odds tend to converge.

(Division % / Wild Card % / Make Playoffs % / World Series Odds)

Astros Fangraphs: Division 9.3% / Wild Card 66.9% / Playoffs 76.2% / WS 10.2%

Astros BP: Division 10% / Wild Card 76.4% / Playoffs 86.4% / WS 8.7%

Rangers Fangraphs: Division 85.2% / Wild Card 12.1% / Playoffs 97.3% / WS 9.8%

Rangers BP: Division 85.8% / Wild Card 10.8% / Playoffs 96.6% / WS 12.6%

Mariners Fangraphs: Division 5.4% / Wild Card 27.1% / Playoffs 33.2% / WS 2.6%

Mariners BP: Division 4.2% / Wild Card 16.3% / Playoffs 20.5% / WS 1.3%

BP’s model continues to be somewhat more bullish on the Astros’ playoff odds than the Fangraphs’ model. But the differences are not large. And the simple percentage of outcomes favoring the Astros (69%) is slightly lower than the probability weighted outcomes of the BP and Fangraphs results.

Potential Playoffs Pitchers

If the Astros make the playoffs, the most likely scenario is that they will face the Twins on Tuesday for a three game series. However, the starting pitcher usage in the Arizona series will have an important impact on the Wild Card pitcher schedules.

Currently, J.P. France is scheduled to start tonight, and Justin Verlander is scheduled to start Saturday. The pitcher for Sunday has not been announced, but Cristian Javier would normally take that day in the rotation.

Presumably the current scheduling would permit Verlander to start Game 2 of the Wild Card on Wednesday. However, if the Astros have not clinched a playoff spot on Sunday, this sets up an interesting pitcher decision for Sunday’s game in Arizona. I have to believe that Framber Valdez would start Sunday’s game if a win is required in order to make the playoffs. In that situation, Valdez’s Wild Card start would be delayed until Game 3 on Thursday, with the possibility that Valdez would not start in the playoffs if the Astros lose Game 1 and 2.

If Valdez has to pitch Sunday, the likely Wild Card starters are Javier (G1), Verlander (G2), and Valdez (G3 if there is a G3). But is their an alternative approach? An alternative decision would start Javier on Sunday even if it is critical to making the playoffs, so that Valdez can start Game 1 of the Wild Card. This would require the Astros to balance the risk of not making the playoffs with the potential to help their odds of winning the WC series.

If the Astros have clinched the WC before Sunday, I assume that Hunter Brown or Jose Urquidy would start on Sunday.

How Likely Are The Astros To Advance In The Playoff (If They Make It)?

This is a popular question among Astros fans. Some might point to the team’s remarkably poor play over the last month, and conclude that the Astros are toast even if they make it to the playoffs. Others might point to their experience as winners in the playoffs, and think that they can “turn it on” when the playoffs begin.

The 2020 playoffs provide some hope for fans who make the latter argument. That Astros team was worse (Win%) than this season’s team, and stumbled to the finish line before making the Wild Card with a losing record. The Astros faced the Twins for the first playoff series, just like they might face them in the first series this year. The Astros swept the Twins, won the next playoff series (against the division winning Oakland A’s), and came within one game of winning the ALCS. So, that Astros team looked quite different in the playoffs than they did in the regular (Covid-shortened) season.

If you want to be optimistic, a recent article by Dan Symborski (developer of the ZIPS projection model) provides a glimmer of hope. Over the years, he has been researching various claims about variables which influence playoff records. Most of the factors claimed by sports pundits are not confirmed by the statistical analysis. But he has a few findings of interest:

  • While regular season record is reasonably predictive of playoff performance, the projection of playoff performance is more predictive;
  • Teams which can hit more HRs have slightly better chances in the playoffs, and those HR heavy teams which will face elite pitching are much more likely to succeed in the playoffs. The intuitive basis for this is that hits and runs are at a premium against elite pitchers, and teams are more likely to win with Earl Weaver’s preferred 3 run HR than sequencing hits together. By the way, over the second half of 2023, the Astros lead the AL in HRs (although the Twins are only one HR behind them), and are 3d in the majors, ranked below only the Braves and Phillies.
  • During the playoffs, projected strength of front line starters become more important than regular season strength. This is because depth is less important in a few weeks of playoffs than it is over a 162 game season. By his measure, the Braves and Astros are the best built teams for post-season performance. Symborski’s Fangraphs article compares regular season strength to post-season strength.

This is fairly encouraging for Astros’ fans, because it suggests that they are the second strongest team in the playoffs, based on variables which are more specific to playoff performance. But I’ll leave it with the more uncertain conclusion of the article.

Is this a guarantee that the Braves and Astros will face off in the World Series? Of course not! We’re not playing the playoffs a million times but once, and when you have only chance, chaos reigns in playoff baseball.