One of the most bizarre facts about the Astros in 2023 was that they were 39-42 at home (tied for 19th best) and 51-30 on the road (3rd best).
The universal question has been "Why are the Astros so bad at home?"
One of my Patreon supporters asked me to go through this rabbit hole and solve this riddle for the Astros fan base. This is a perfect topic for us at LarryTheGM.com. So perfect that I am tempted to give it to my Patrons only for a week because I have no fear that anyone is going to address it as deeply as I am about to. Consider this your holiday gift that you are getting part of the answer today. Repay that gift by supporting the site at Patreon here. Consider it your Christmas gift to me for all of the content this year.
Today, let's focus on how the hitting caused the Astros to struggle at home in 2023 relative to the team on the road. This is a two-part series. Next week we will address the pitching side of this issue.
Hold on readers. This is going to be a data avalanche.
Let's start high level with some basic data.
The Astros scored 4.51 runs/game at home. They have a negative wOBA gap at home meaning the wOBA was lower than the xwOBA which means that based on the contact made they SHOULD have hit better. This unlucky reality accounts for about 0.25 runs/ game. Part of that difference is explained by a home BABIP of 0.285 which is below the league average of 0.299. The home wRC+ of 105 was slightly above league average at home. Overall, the models I have built would project that the Astros SHOULD have scored 4.67 to 4.92 runs per game - more than the 4.51 runs /game they did score.
Almost everything on the road is the opposite where the Astros scored 5.70 runs per game. The team had a positive wOBA gap away meaning the wOBA was higher than the xwOBA which means that based on the contact made they SHOULD have hit worse. This lucky reality accounts for about 0.13 runs/ game. Part of that difference is explained by a road BABIP of 0.303 which is above the league average of 0.295. The away wRC+ of 118 was significantly above league average on the road. Overall, the models I have built would project that the Astros SHOULD have scored 5.24 to 5.37 runs per game - significantly less than the 5.70 runs /game they did score.
They were unlucky at home and lucky on the road.
There is a theory first proposed by Bill James called the Pythagorean Theorem. It is described here on Baseball Reference. It calculates a predicted win percentage based on the runs scored and given up.
Here is the breakdown of what the result should have been (data included from the pitching article now complete.)
If I consolidate the actual runs produced data by the offense we discussed previously and the runs given up by the pitching, we get one view of the performance. However, if I consolidate the same data for the PROJECTED runs, it shows the net effect of luck.
The Astros won
39 games at home
51 games on the road.
Based on their actual runs produced, the Astros SHOULD have won (per the Pythagorean runs theory)
39 games at home
54 games on the road
Based on the PROJECTED runs they SHOULD have scored (via xwOBA model), the Astros should have won
43 games at home
43 games on the road
Yes, the Astros should have been better at home. They SHOULD have been significantly worse on the road. In fact, if the Astros had won the games their performances project to without luck, the team would have won 86 games in 2023. That means they would have missed the postseason.
The lowest projection for the road Astros offense is 5.24 runs/game and the highest for the home Astros offense is 4.92 runs per game. Why are they scoring more on the road than at home?
To answer that we are going to look at the individual players.
I have provided the home and away data for wOBA/ xwOBA, BABIP, wRC+, and exit velocity. This data will enable us to investigate the difference of how each Astros player performs at home vs. away. The cells in red are extreme outliers. the cells in orange are significant differences. In the table below, I also show those difference over that players career.
A few highlights-
Jose Altuve's massive road BABIP (0.372- 15th highest of 277 MLB regulars) fueled a HUGE wOBA gap on the road. This made Altuve unstoppable on the road and catalyzed the offense. He hit with normal BABIP luck at home.
Kyle Tucker had a terrible BABIP luck at home (243rd out of 277). This fueled his home negative wOBA gap. Bregman had an even worse home BABIP but it did not impact his home performance as much.
Jose Abreu had the Astros worst home wOBA gap.
Jeremy Pena had a road BABIP just a notch below Altuve but it did not translate into the massive positive wOBA gap on the road.
Not all of the gaps favored the road over the home performance.
Chas McCormick had a high BABIP at home and this brought a positive home wOBA gap for McCormick and made him better at home than on the road.
Martin Maldonado had a terrible 0.221 BABIP (270th out of 277) on the road and this depressed his road performance. More on this later.
Yainer Diaz did the incredible feat of having a sky-high home BABIP (0.343- 50th out of 277) and an incredibly low road BABIP (0.236- 259th out of 277). This pumped up his home performance 164 wRC+ and suppressed his road performance (87 wRC+).
We can explore the comparison of Home vs. Road numbers for these stats as well to highlight difference in approach and also further highlight the other impacts.
This data is sorted by the players who performed far better away than at home. Many of the players have different dynamics driving their gaps. Notice the biggest away players are probably the most important to the Astros office- Altuve, Alvarez, and Tucker.
What is fascinating in these differences is to see where there is a wOBA home/ road difference but there isn't in the xwOBA data.
This is the case for Altuve, Meyers, Pena, and Abreu. One might say that this is an indicator of bad luck. Pena and Abreu actually had better xwOBAs at home than the road. They had better contact with worse real results.
Alvarez has both a large wOBA home/road difference and a xwOBA home road difference. He just did NOT hit as well at home. Is he pressing at home? This is validated by the exit velocity data. Alvarez has a massive velocity drop at home vs. road - 4.5 MPH. This is the biggest home exit velocity drop of ANY of the 277 MLB regulars in my comparison group. His iso was 0.210 home/ 0.371 away. Maybe it is a batter's eye issue for the LHH.
Similarly, comparing the home and road BABIPs leads to some interesting theories.
Pena had a -0.092 home to road BABIP difference. This was the 11th biggest gap favoring the road. He was exceeding lucky on the road and average at home.
Julks, Tucker, and Altuve had similar BABIP gaps favoring them on the road.
Maldonado and Diaz had the opposite. Diaz had the 4th biggest home over road BABIP difference and Maldy had the 20th. Home was good to the catchers.
You may be wondering how one can raise their BABIP. It is different for each player. Maybe a focus on barrel contact (not all contact is created equal.) For others it may be an overswinging issue or trying too hard. One would study the details for each player.
The exit velocity data shows some of the extremes the Astros hitters had home vs. road.
I already told you that Alvarez had the biggest road over home in the MLB among the 277 players who had a significant sample size of both road and home PA. We said this COULD be the batter eye issue.
Madonado had the biggest home over road velocity gap - 6 MPH!!- among all of the 277 MLB players. How does one have such a huge advantage at home over road? I don't know.
OK are you confused yet?
When someone asks why the Astros were better hitting on the road than they did at home, the best answer will be to say "Well, it is complicated and link them to read this." (Kidding)
Let's summarize what we would say about each player.
Altuve- MASSIVE ROAD BABIP. Led to massive road wOBA to xwOBA gap. Led to a massive road over home wOBA difference. xwOBA gap and exit veloity difference in normal range. Luck on the road.
Alvarez- MASSIVE improved exit velocity on the road leading to a huge difference in Iso on road ove home. Led to road performance far outpacing home.
Tucker- Terrible BABIP luck at home having a significant performance improvement on the road. There is also a modest exit velocity increase on the road which also fuels his road increase.
Dubon- similar profile to Tucker on a smaller scale. Better BABIP luck on the road. Better exit velocity on the road. Dubon experienced two big slumps at home April and July (slumped in July at home and road but worse at home.) It may be possible he was pressing at home to fill in for the injured Altuve at the start of the season.
Meyers- Has been better on the road for his career. Maybe he presses at home. His home BABIP was a little worse.
Julks- Home BABIP was far worse than the road. Significant velocity drop at home.
Bregman- How does Bregman have a 0.252 BABIP at home? Significant wOBA gap. No other metrics truly stand out.
Pena- MASSIVE road BABIP probably enabled modest performance difference. Pena had a -0.092 home to road BABIP difference. This was the 11th biggest gap favoring the road. He was exceeding lucky on the road and average at home.
Abreu- had the Astros worst home wOBA gap. xwOBA indicates he sohould have been better at home.
Then there were the few Astros regulars that did better at home.
McCormick- High BABIP at home, positive home to road WOBA difference.
Maldonado- Had a terrible 0.221 BABIP (270th out of 277) on the road and this depressed his road performance. Madonado had the biggest home over road velocity gap - 6 MPH!!- among all of the 277 MLB players.
Diaz- Did the incredible feat of having a sky high home BABIP (0.343- 50th out of 277) and an incredibly low road BABIP (0.236- 259th out of 277). This pumped up his home performance 164 wRC+ and suppressed his road performance (87 wRC+). Diaz had the 4th biggest home over road BABIP difference.
Well, these are my reasons the Astros offense struggled at home in 2023 vs. how well they did on the road. It is not ONE thing; it is several things. Most of these are LUCK related. Some of them require a review of a player's approach at home vs. away. Yes, one of them at least may validate a review of the batter's eye. Combined together, psychologically a team could easily start to BELIEVE they are not good at home and play better on the road. I think by mid-season THIS played a role as well.