The Astros at the Midway Mark

PLAYOFF RACE

With 52% of the season behind them, the Astros battle for a playoff spot—whether as the AL West division champion or a Wild Card team. The remaining 48% of 2023 games provide a broad canvas for future ebbs and flows in the team’s fortunes. On July 4, the Astros are three games behind the Rangers in the AL West.

By winning 3 of 4 in the Rangers series over the long weekend, the Astros significantly improved their playoff odds, according to Fangraphs’ model. Last week, the Astros had a 27% chance of winning the division and 56% odds of making the playoffs. On July 4, the Astros odds improved to a 38% chance of winning the division (more than ten percentage points higher) and a 70% chance of making the playoffs.

As I have noted in previous articles, Baseball Prospectus PECOTA model is even more optimistic for the Astros. PECOTA standings show the Astros with 57% odds of winning the division and 82% odds of making the playoffs. PECOTA expects fairly steep regression by the Rangers.

Heading into the Fourth of July, the Astros are in a pretty good position to battle for a playoff spot. The odds will have peaks and valleys going forward, but many teams would like to be in their position.

Now, let’s talk about defense at the midway mark.

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TEAM DEFENSE

Let’s look at the current status of the advanced defensive metrics. The two primary defensive measurement systems are the Fielding Bible’s defensive runs saved (DRS) and Baseball Savant’s outs above average (OAA).

DRS provides an interesting perspective on the AL West divisional battle between the Rangers and the Astros. Most commentators focus on the Rangers’ offensive firepower and the Rangers’ off-season pitching acquisitions to explain why the Astros find themselves trying to chase down the Rangers. But this overlooks an equally important element of the game—team defense.

So far this season, compared to 2022, the Astros have taken a step back on defense, and the Rangers have improved their team defense significantly. The impact of the change in defensive runs saved also will be embedded in the teams’ ERA. (Note that the Astros are ranked 8th and the Rangers 3d in OAA; however, the OAA runs saved comparison is essentially the same as DRS.)

In 2022, the Astros were the fourth-best team in defensive runs saved. To this point, in 2023, the Astros are the thirteenth-best team in defensive runs saved. The Rangers have vaulted from 20th in DRS in 2022 to No. 1 in DRS in 2023. In order to compare 2022 and 2023, I will prorate the 2022 defensive runs saved by the number of games played in 2023. If the Astros had performed at their 2022 fielding proficiency, the team would have 26 fewer runs allowed in 2023. The Astros’ decline in DRS is approximately equal to 2.5 fewer wins.

The Rangers, on the other hand, have so far increased their defensive runs saved by 42 runs in 2023, which is equal to a gain of 4 wins. The combination of the Astros' defensive decline and the Rangers' fielding improvement, compared to 2022, is about 6.5 wins— which significantly exceeds the Astros’ games behind in the standings. So, yes, the defensive impact is a big deal. Of course, 48% of the season remains to be played, and the fielding metrics can be volatile in small samples. So, the future direction of the Astros’ and Rangers’ defense will likely be a significant factor in determining which team wins the division.

The Fielding Bible’s current accumulation of team defensive runs saved is linked here.

• The Astros are seven runs saved above average. The positive DRS is highlighted by CF and 3d base, which each provide +6. Other positive contributors, by position: 2d base (+3) and shortstop (+5). RF is the most significant problem at -7. Other negative contributors by position: Pitcher (-1), Catcher (-5), and 1b (-1). LF is precisely average (0). Some of what we label as pitching regression this year probably is caused, instead, by the defense.
• So far this year, the Rangers are 45 defensive runs saved above average. The Rangers have no negative defensive positions. Significant improvements have shaped the defense in CF (+10), 3d base (+3), 2d base (+6), and 1b (+5).
• Part of the Astros' fielding decline is associated with a rule change (the infield shift rule) as opposed to individual fielders’ proficiency. The Astros were at the forefront of using the infield shift for run prevention. A large proportion of the Astros’ defensive runs saved last year were the result of the shift. Therefore, the Astros’ fielding metrics are hit harder by the shift rule than other teams’. Based on a comparison of DRS between 2022 and 2023, the Astros so far have allowed 14 more runs due to the abolition of the shift. This is equivalent to losing 1.5 wins.
• The change in BABIP allowed by Astros’ pitchers is consistent with less effective run prevention caused by the prohibition of the infield shift. Astros’ pitchers’ groundball BABIP is .248 compared to .216 in 2022. Last year, the shift also allowed more line drives to be caught in the shallow outfield by an extra infielder. Since this is now prohibited, more line drives are falling in safe. The BABIP on line drives against Astros’ pitchers has increased noticeably. The line drive BABIP was .595 in 2022 and is .631 so far in 2023.
• The increase in groundball and line drive BABIP produces 14 more runs allowed—which also happens to equal the DRS estimate of the impact of the shift’s rule on the Astros' defense. This seems to confirm the Fielding Bible’s run value for the Astros’ implementation of the shift last year.

So, what can the Astros do to improve their DRS? The options are fairly limited, and the best answer is the simplest: the Astros’ players just have to play better defense, improving their execution in the field. The most disappointing player on defense is Kyle Tucker. But we know he is capable of better defense in the future. It’s possible that the Astros’ DRS will improve at the catcher position if Diaz receives more regular starts at catcher.

Another area of potential improvement lies in positioning players in the field. Although the infield shift is banned, more limited shifting of infielders on each side of second base is allowed by the rules. The Rangers appear to have done a better job of positioning infielders and outfielders than the Astros. The Astros are +6 DRS, and the Rangers +12 DRS for infielder shifts and OF positioning. The fact that the Rangers can wring twice the runs saved out of fielder positioning suggests that the Astros have room for improvement.