The Ultimate Houston Astros ALDS Matchup Guide

Updated: Oct 11

Here is EVERYTHING you need to know about the ALDS for the Houston Astros vs. the Seattle Mariners.


This guide is going to make far more sense if you take the time to read these first

Mid September Pitching Roster Prediction

Who is Hot and Not for the Astros

My Astros Batting Roster and Lineup


This article is going to have a mountain of data. I am going to produce my first LarryTheGM video to talk you through it.


Call up this video on YouTube and follow along as we talk through this article. The data here will make a lot more sense if you do.


Don't worry if the data journey is difficult, the end point will give you a nice matchup matrix to refer to and the likely series MVPs for each team.


Let's Start with an overview of both teams. You will see the familiar heat map formatting (Red Good/ Blue Bad). Here is the overall grid.

Houston accumulated the second highest WAR and Seattle the 12th.


The Astros had the number one pitching WAR. Seattle had the 16th best pitching WAR but improved significantly when they acquired Luis Castillo.


The Astros had the sixth best batting WAR and Seattle had the ninth best batting.


Let's look at the pitching in detail.


Seattle Pitching


The Seattle pitching is good. They probably have 9 to 10 really good pitchers. The challenge for the Astros is in a short series, a team does not need more than that to win a series. Their Bullpen is the strength of the pitching.


In GENERAL, one might say most of the starters are stronger vs. LHH and most of the bullpen is stronger vs. RHH. (See the xwOBA columns on the right.)


Houston Pitching

The Astros are AMAZING as a pitching staff. Look at ALL this red!


As a whole the pitchers have been good vs. BOTH LHH and RHH. EVERY Active Pitcher for the Astros (14) has a season ERA equal to or better than the MLB Average ERA this season- 3.97.


Will Smith has been VERY Good as an Astros pitcher as shown by his stats on his second line above. I WOULD have Smith on the ALDS roster.


If the Astros agree, I believe the twelfth and final spot on the ALDS roster will come down to Maton, Urquidy, and Garcia. We will detail that as we look at the matchups.


Now looks look at the position player lineups


Seattle Batting Lineup


The Mariners are good one through six. Seven through nine is not great. Expect Moore to platoon most likely with Frazier vs. LHSP Framber.


Houston Batting Lineup

This SHOULD be the lineup in General vs. the Mariners but it is not likely to be. Gurriel and Maldonado do not deserve to start in critical postseason games. I will show you the impct more in the matchups grid.


Before we go on, you will notice I have included xwOBAs for every pitcher and batter vs. both LH and RH opponents. These are critical building points in this analysis.


Building the Matchup Grids- xwOBA data- Seattle


As we build our matchup guides we are going to focus on xwOBA stats. We are going to pull xwOBA for ALL of the players shown and BY PITCH TYPE and PLATOON.

Seattle Hitters xwOBA by Pitch

Again focus on the heatmap aspect of this vs. individual numbers. You can see for any of Seattle's batters what pitches they do well at and what pitches they struggle with.


To be fully transparent, I do not know what a minimum sample size needs to be here. I filtered out data where there is no way the data is representative.


Seattle Pitchers xwOBA by Pitch


Next is the Seattle pitchers grid.

With a glance you can see what a pitcher has thrown well this year and where they have struggled. For each type of pitch, I am showing the percentage that that pitch is thrown and the xwOBA.


For example, Luis Castillo throws his 4-seam fastball 29.4% of the time to RHH with a xwOBA of an excellent 0.198. If you see that you know how to read that table.

Now let's look at the Astros grids.


Astros Hitters xwOBA by Pitch

This is the data you should look at when someone tells you "Gurriel is great at hitting changeups." Yes, but only if thrown by a RHP. If you can see that in the table above you got this.


Now the Astros Pitchers


Astros Pitchers xwOBA by Pitch

Do you notice that 4-seam fastballs seem to get hit pretty well off of most pitchers? Notice all of the red pitches for the Astros? Yeah they were great.


Creating the Matchup Grid


Now that we have the xwOBA data for both hitter and pitcher we create the matchups. I have created one of these for all of the pitchers previously shown that I had xwOBA data for.


Here is what the grid looks like for Verlander


The data in the black boxes is what Verlander's data was on the previous table. The data in the green box comes from the Mariner's hitters table previously shown (vs. RHP).


The data in red font is the matchup answer. This shows what each batter based on

1. JV's pitch distribution (the pitch percentages)

2. JV's pitch quality (his xwOBAs)

3. The Mariners hitting quality (their xwOBAs)


would expect to do vs. Verlander. Obviously with Verlander, there is a lot of blue for the batters.


Note: for the Seattle switch hitters - Santana, Raleigh, and Toro- I labeled them R or L based on the handedness of the SP.

As mentioned, I did this for every pitcher vs. every batter. He are the overall matrixes.


Houston Hitters vs. Seattle Pitching

The yellow cells are where there is not enough data.


Notice the black, red, and green boxes. The red box indicates a bench player would be a better option to start. They would be replaced by the player in the green cell.

  • Gurriel replaces Mancini for a Robbie Ray start

  • Meyers replaces Diaz in a George Kirby start (Meyers CF, McCormick LF, Mancini 1B)

  • IF Chris Flexen got a start, Meyers would replace Diaz as well.

The Black boxes show the best PH to use. This is especially important vs. the relief pitchers. Notice that for FIVE key Seattle RP, Matijevic, yes Matijevic, is the best and in some case only viable choice to use as a PH. The data for Henley is so limited, but I would. assume he would be first choice as PH in many situations.


To me this means Matijevic SHOULD be on the ALDS roster if the Astros play the Mariners.


Also notice that Maldy is NEVER a better choice to start than Vazquez.


So if the Astros can carry 14 bats and we have the nine starters, Gurriel, Maldonado, Meyers, Henley, and Matijevic; there is no slot for Dubon. If Dubon is the 3rd best PH option, then I do not think this is a loss. Henley, Meyers, and Diaz can cover any defensive replacement needs. Why would the team need Dubon?


Other notes=

- Munoz is going to be an issue for the Astros. Castillo will be as well.

- The Astros would do best to hit the SPs


I sorted the data in the last two columns to show who the Astros can count on the most in this series at the plate.

This table has the last two column of the previous table and then a weighted average (2/3 SP and 1/3 RP) to project an overall ALDS projected xwOBA for each Astros hitter. Alvarez is by far the one Astros batter this system projects to rake- surprise! Now notice the bottom of this table.

  • Diaz will likely struggle against the RPs

  • Matijevic could be a KEY PH late in games.

  • Vazquez's 0.280 xwOBA vs. Maldonado's 0.221 xwOBA (horrible- his 70 wRC+ season was a 0.253 xwOBA) make Vazquez the needed starter

  • Dubon projects to be bad overall- he is really only a viable hitter

  • vs. Gonzalez (who may not be on Seattle's ALDS roster )

  • vs. SP (Ray and Gilbert) for whom there is a better starting and other PH options

  • I don't see where ho SHOULD be played

  • Gurriel projects overall to be worse than Dubon BUT should start vs. Ray

  • Meyers will struggle except vs. Kirby and Flexen. However, his season data may not be reflective of where he is at physically NOW. He should start vs. Kirby

  • Overall vs. the strong Seattle pitching Houston projects to have a xwOBA of 0.302

How will Seattle do vs. the even better Houston pitching?


Let me first share how the two pitching staffs compare.

Yes, the Astros staff projects to be even better than the Seattle staff. Notice the two lines for Will Smith. One is his overall season numbers and the other is his Houston only numbers - significantly better.


Seattle Hitters vs. Houston Pitching




Notice all the blue for the Seattle offense. The Incredible Astros pitching staff projects to throw some gems at the Mariners.

Expect the Mariners to try to matchup as positively as they can based on data very similar to this grid.

Some Astros Pitching notes based on this grid and pitching summary:

  • I provided the data for Will Smith based on his season stats and his Astros stats as detailed in this article. Based on his Astros stats Smith would be an EXTREMELY valuable weapon vs. the bottom of the Seattle lineup AND France, Suarez, and Raleigh. Read a lot more about how this has happened in the link.

  • Valdez projects to have a real challenge in this series with the second highest projected xwOBA

  • Javier projects to be the best SP. Yes you read that correctly.

  • Pressly, Montero, Stanel, and Neris mean game over.

  • I would project Maton, Urquidy, and Garcia to be competing for the 12th roster spot. I think the Astros pick Garcia. His xwOBA of 0.307 is better than Maton (0.313) and Urquidy (0.340).

How does the weighted average of the Seattle hitters look vs. the Astros Staff?




Suarez and Santana are really the only batters that project to be better than average.


Overall vs. the epic Houston pitching Seattle projects to have a xwOBA of only 0.277.


You heard it here first. Houston pitching shuts down Seattle. Astros win in 4.


Likely MVPs


Offensive MVPs

Astros- Alvarez

Mariners- Suárez


Pitching MVPs

Astros- Javier and Pressly

Seattle- Muñoz and Castillo


My Final Astros ALDS roster prediction

I am including who I think the Astros will have on the roster and who I WOULD have on the roster based on these matchups.


Now that you have this data, you will not watch these games the same ever again. Keep these tables near you as you watch and monitor how well the xwOBA tracks what happens. When there is a pitching change you can use these to see what move you would make.


The data work here has been grueling. If something looks wrong, PLEASE tell me and I will check it.


PLEASE let me know what questions you have here. Monday, I plan on recording a YouTube to walk through the data here. Sunday and Monday Night, I will be on Twitter Spaces. Look for me on twitter @LarryTheGMman.


The statistics referenced here come from Fangraphs.com and baseballsavant.com


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