The Astros at Memorial Day. Theme #4: The Defense Has Made Improvements
This offseason, the front office decided to prioritize infield defense and sacrifice some outfield defense. That decision has worked to the Astros benefit so far in 2025.
In the offseason, the Astros made a massive change to their every day lineup. They moved Jose Altuve, who had been their everyday second baseman since being called up from the minors in 2011, to left field, where he started on Opening Day.
They made this move to address Altuve’s declining defense at second base. Father Time is of course undefeated and Altuve’s range at second base had declined significantly over the last several seasons. They turned second base over to a job share between Brendan Rodgers and Mauricio Dubon, both superior defenders.
The Astros also made a move at first base to address their defense, signing Christian Walker, who had won the last three National League Gold Gloves at the position. In 2024, the Astros relied on a combination of the washed-up Jose Abreu, the statuesque Jon Singleton, and two catchers playing out of position in Victor Caratini and Yainer Diaz.
In short, the Astros font office identified a weakness on the team—infield defense—as made moves to address it. And to address it, they were willing to sacrifice some defense in left field by moving one of their infielders to a completely new position.
Early returns on this move are positive. Most indicators find that the Astros have overall made modest improvements in their team defense in the 2025 season. And specifically, the emphasis on infield defense over outfield defense has worked. The team’s defensive improvement at 1st base and 2nd base has outstripped their decline in the outfield.
Let’s dig into the numbers.
Improved Defensive Efficiency
Defensive is very difficult to measure and different systems of calculating defensive output come up with different results.
One simple measure of defensive ability is defensive efficiency. I like to use it because it is a very simple measure—it simply measures the percentage of balls hit into play that are turned into outs. In 2025, the Astros have a defensive efficiency of .719. That is, they have turned 71.9% of balls hit into play into outs. Is that number good? Yes, it is the sixth best rate in the majors.
More importantly, it’s an improvement over the .704 defensive efficiency measure that the Astros recorded in 2024. The 2025 Astros are converting 1.5% more of their opportunities into outs. The 2024 numbers were good—the Astros were 9th in the majors in defensive efficiency. The 2025 numbers are of course better. The Astros are getting more outs, which of course leads to fewer runs allowed.
Defense has been one of secret strengths of the Golden Era Astros. They have finished in the top 10 in the MLB in defensive efficiency every year since 2018 and were above. 715 in this metric in 2019, 2021, and 2022. But the Astros defense slipped in 2023—their .697 number was 10th best in the majors—and 2024—as noted, their .704 number was 9th best.
Strong Improvement at First and Second
The front office’s plan to improve the team defense for 2025 was to focus on the infield defense, making improvements at first and second base, while being willing to sacrifice some outfield defense, as the moved Altuve to left field and let Cam Smith, who was a third baseman in college and in the minors, play right field.
Early numbers show that this choice has worked out for the Astros. You can see that in the chart below, which shows the improvement (or lack thereof) in Outs Above Average for the Astros at each defensive position.
What is clear from the chart is the massive defensive improvement at first and second base. In 2024, Astros second basemen (mostly Altuve) recorded -7 Outs Above Average. In just one-third of a season, Astros second basemen have recorded a +10 Outs Above Average. That’s a 17 out difference, in just one-third of the 2025 season.
At first base, Chrisitan Walker has not recorded a strong defensive performance so far. He and his backups have combined for -1 Outs Above Average. But that is a massive improvement over the -13 Outs Above Aveage recorded in 2024.
Astros infielders are getting to more balls than last season. That is also true at shortstop, where Jeremy Pena is having a better defensive season in 2025 than he did last season. At third base, Isaac Paredes is just 1 Out Above Average below what Alex Bregman recorded last season.
Of course, the Astros made some defensive trade offs this season by sending Altuve out to left field. The defensive performance in left field has declined in 2025, but only by 3 Outs Above Average from 2024. Last season, Astros left fielders were neutral; this season, they are -3 Outs Above Average.
It’s a decline, and one that will grow over the course of the season. But it’s a much smaller decline than the gains we see at first and second base.
One can see that the Astros biggest defensive decline is in center field. And that shows one issue with comparing partial season numbers (2025) to full season numbers (2024). In 2024, Astros center fielders—led by Jake Meyers—were excellent defensively, recording 15 Outs Above Average. That was 3rd best in the majors.
This season, Astros center fielders (again, almost all Meyers) have recorded 6 Outs Above Average. If they keep that pace up all season, then they will meet and exceed last year’s number.
I write all that to make two points. 1) Jake Meyers remains a top class defensive center fielders, and that provides a lot of value to the Astros. And 2) these are preliminary numbers. Thus they are worth checking on throughout the season as we get more data on defense.
An Effective Trade-Off
But the preliminary numbers I have shown here are quite encouraging. The Astros have made big defensive improvements at first base and second base, and that is quite outpacing their modest defensive decline in left field.
The front office made a choice to emphasize infield defense over outfield defense. This is probably a good choice for any front office. For example, so far this season, MLB second basemen have recorded 4,102 assists. That is much larger than the 3,136 putouts that MLB left fielders have recorded.
But it is a particularly good choice for the Astros. The top 2 pitchers in the Astros rotation—Hunter Brown and Framber Valdez—are ground ball pitchers. This season, they have the 21st and 6th highest ground ball rates respectively among the 80 qualified starting pitchers.
Valuing infield defense helps to maximize the value of the Astros top two pitchers. The Astros need a high quality infield defense. So far in 2025, they are getting it.
Great analysis