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The Astros advance to the ALDS: a sabermetric review

The science (kind of, again) behind the victory over the Yankees.

Adam Hunger-USA TODAY Sports

The Houston Astros have made it into the real playoffs, rejoice! Dallas Keuchel, resident ace, a few big home runs, and a solid bullpen effort were, collectively, enough to see off the New York Yankees. The youngest team in baseball, on average, saw off the oldest team, and will now advance into the American League Division Series, to face off with the Kansas City Royals.

In order to celebrate this monumental achievement; have some sabermetric titbits.

Throwing six shutout innings, walking only one batter while striking out seven, Keuchel was on his game. He made very few mistakes all night long. However, he did make big mistake. A pitch right over the heart of the plate to Alex Rodriguez, with two runners on, could've seen the Yankees take the lead. However, Rodriguez merely flew out, softly, to Carlos Gomez. Panic over.


According to Fangraphs, Keuchel threw just nine pitches over the heart of the plate, or 16% of pitches, if you will. The lowest percentage of pitches thrown over the heart this season from a pitcher was Kyle Gibson's 15%. So, yeah: Keuchel was pretty stingy last night with pitches to hit. (Not a single one of the pitches was from ahead in the count).

Here's a look at the WPA graph from last night;

Source: FanGraphs

So, the first inning was the only time the Yankees had a higher likelihood of winning than the Astros. Tanaka was extremely sharp in the first inning, striking out two, while Keuchel struggled through the first; he walked a batter, and pitched himself into a full count against the leadoff hitter. Other than that, flawless.

Colby Rasmus hit a bomb off of the first pitch of the second inning and the Astros never looked back. After Carlos Gomez's home run, the only time the Yankees truly threatened at getting back into the game was in the sixth. But, Keuchel was on the mound, Keuchel was dealing, and here we are now; heading to the ALDS.

The leverage index is interesting. Concerning bullpen use, the bottom of the seventh inning was clearly the most important and most taxing inning. It's interesting, therefore, that Sipp pitched the entire inning, yet Gregerson was saved for the ninth inning save. So un-sabermetric, Houston. (Just kidding, of course).

Breaking down the WPA for each individual action last night, and there were some undeniable key moments in the game: Colby Rasmus' home run, Carlos Gomez's home run, Alex Rodriguez's fly out with two runners on, Jose Altuve's RBI single and overall, Dallas Keuchel's entire outing. The moments that mattered, you could say.

The strike zone caused some problems last night. And when I say it caused some problems last night, I mean it caused some problems for the Yankees, namely; Brian McCann. McCann was not happy with some Eric Copper's calls, so much so, he was seen swearing live on ESPN. Nice work, Brian. Anyway, it seems the strike zone was actually pretty fair, accurate and consistent.

chart (22)

My favourite thing from the game? The single biggest moment of the game for the Yankees (Rodriguez's fly out), came on Keuchel's biggest mistake of the game. Baseball is weird, but right now, baseball is a lot of fun. See you all in the Division Series. This whole postseason thing is a lot of fun.

Thanks to Fangraphs for all of the above graphics and charts.