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Eliminating the Shift will Affect the Astros

But How Will It Affect the Astros? Hard to Know.

MLB: Houston Astros at Detroit Tigers
Yordan Alvarez hitting the ball for a double to left field in Detroit’s Comerica Park.
Lon Horwedel-USA TODAY Sports

The infield shift will be eliminated next year. The rule change will affect all teams—but that’s particularly true of the Astros. The Astros have been the top employer of defensive shifts over the last ten years. And Astros’ batters face defensive shifts a high percentage of the time. At the risk of spoiling the plot, it is very difficult to determine how the rule change will affect the Astros.

Although this article will primarily address the offensive impact, we do have a reasonable estimate of the impact on Astros run prevention. Team Defensive Runs Saved (DRS) are shown in the Fielding Bible. DRS is based on runs saved above average, and infield shifts are counted as team (not individual) defensive runs saved. According to that measure, the Astros’ infield shift saved 35 runs, which is the second highest of any team (only the Dodgers received more benefit from the shift). That is more than half of the Astros’ total 67 defensive runs saved above average and is equivalent to 3 - 4 wins. Trying to estimate how the shift will affect particular pitchers is much harder. If 35 more runs will be scored on the Astros due to the shift—and since this number applies to 2022, we don’t know for certain if it will apply to 2023—the distribution of the higher runs allowed among pitchers is unknown. I’ll save that discussion for another day, and turn now to the offense.

Of course, the net impact of the rule change on the Astros depends on any benefit that Astros’ hitters receive from the rule change. And this turns out to be more complicated than you might think. Sure we know the general direction of the impact, and we can generalize that left-hand batters are affected the most. But actually quantifying the impact runs up against a number of obstacles.

Let’s just say that the most accurate method would be a granular approach for each player that evaluates the batted ball location on the field relative to the defensive positioning. Such an approach is data intensive and is more precise than comparing offensive stats with and without shifts.

Adding to the complexity of forecasting the impact of the rule change, teams may still employ “partial shifts” which comply with the rule change. This may not be as effective as the outlawed full shift, but it may prevent more runs than the traditional defensive deployment. An example would be placing the shortstop up the middle without crossing second base and deploying the third baseman in the normal shortstop position. A riskier option is placing the LFer in short RF. The point is that we don’t know how defenses will respond to the rule change, nor can we predict how much partial shifts might offset some of the added runs allowed by the rule change.

Furthermore, the shift seems to produce behavioral changes in the batter and pitcher that are not clearly explainable. An article by Mike Petriello discusses some of those factors.

  • Walks increase vs. the shift. Perhaps the pitcher is less inclined to pitch to the outer third of the plate to avoid slap hits, or maybe the hitter becomes more patient against the shift.
  • Strikeouts increase vs. the shift. Unclear if this is due to changes in pitching strategy or the batter altering his approach.
  • Some evidence indicates that HRs are more likely vs. the shift. This may be due to batters trying to hit “over” the shift. Also, batters tend to hit the ball harder when they face the shift (perhaps because they are pulling the ball into the teeth of the shift). But the cause-effect relationship here is not clear or definitive.

The tweet below is related to this issue and shows an interesting picture of an Astros’ shift.

Astros Batters Likely To Benefit

Sports Information Solutions (SIS) has used 2022 data to project the 18 MLB batters who are likely to benefit the most from banning the shift. Three Astros—Alvarez, Bregman, and Tucker—are on this list of the top beneficiaries of the new rule. As part of this analysis, SIS assumes that partial shifts will reduce the run impact in some cases. The headliner on this and other articles about the shift is that the Rangers’ Cory Seager is expected to benefit the most of any MLB batter. His OPS would increase from .772 to .836 in 2022 without the shift. Yordan Alvarez is tied for second behind Seager; Kyle Tucker is seventh, and Alex Bregman—a righthand batter—is tied for tenth on the list.

The table below shows the net increase in hits in 2022, according to SIS, without the shift. I also have converted the hits to runs, based on a rough 2 to 1 ratio.

Net Increase in Hits / Runs

Alvarez 13 / 7.5

Bregman 10 / 5

Tucker 13 / 6.5

Total 38 / 19

I recalculated each player’s wRC+ with the additional runs above. The percentage increase in wRC+ for Alvarez is 7%, Bregman 5%, and Tucker 6%. In addition, I also examined Michael Brantley, another lefthander on the roster. Fangraphs wRAA (runs above average) data in shift situations suggests that he would benefit in a manner similar to Tucker and Bregman if he had played the full season. I estimate 5.1 runs added to Brantley, in the absence of the shift, if he had played a full season. (Instead, Brantley’s season was shortened by injury.)

Astros Team Offense

The final part of my analysis considers the impact on the Astros’ total offense. Unfortunately, I don’t have the kind of granular batted ball analysis (similar to the SIS study above) that would produce more accurate results. Instead, I utilized Fangraphs team wRAA (runs above average) data for the overall 2022 Astros, as well as wRAA data for the Astros’ team splits against the traditional shift defense.

The Astros faced a defensive shift in 41% of plate appearances. When facing shifts, the Astros’ were -60 runs, compared to +69 runs on an overall team basis (including both shifts and non-shift situations). My analysis attempted to solve for the additional runs which would have been scored if the wRAA rate was the same for both shift and non-shift situations. An additional complication is that the elimination of shifts will increase the league average runs, which in turn increases the baseline for wRAA. Therefore, I made an adjustment for this effect based on league wRAA versus shifts.

Based on this analysis, the Astro's wRAA would increase 36 runs without the shift. If it’s accurate, the additional offensive runs are virtually the same as the Astros loss of runs saved on the defensive side. However, I think it is likely this type of analysis will overstate the offensive impact of eliminating the shift. The analysis basically assumes that all of the wRAA difference between shift and non-shift situations is caused by the shift. However, that assumption probably ascribes excessive run impact to the defensive shift.

That is why a more granular analysis of batted balls is preferred. Examining the SIS results for Bregman, Alvarez, and Tucker, it appears that this more granular approach results in a run impact which is 20% - 30% of the impact indicated by Fangraphs wRAA data described above. If a similar percentage were applied to the Astros wRAA, the increase in runs without the shift would be approximately ten runs instead. And as a result, the loss in run prevention would exceed the Astros’ offensive gain by about 15 runs.

The bottom line is that these team calculations for the offensive impact of the shift are too uncertain to reach any conclusion about the impact on the Astros team stats. Given the number of variables that could impact the result, we will have to wait for the season to play out to reach a conclusion about the impact on the Astros.

MLB: Minnesota Twins at Houston Astros
Jose Altuve, shown playing defense in 2013, is a key defender in the Astros’ shift.
Thomas Campbell-USA TODAY Sports