The Astros Early Season and the Shift Rule

I’m not really comfortable writing about the Astros after only a handful of games. The reason is obvious: a super small sample size. Basically, early season stats don’t mean a lot, because they may be totally unrepresentative of what we know a month, or several months, from now. But still we want to look and see if they suggest something.

How has the prohibition against the shift affected the Astros so far?

As most everyone knows, MLB prohibited moving infielders into a shift defense. This may hurt the Astros’ run prevention because the Astros were the second-best team at preventing runs with the shift defense. Conversely, the Astros' offense may benefit from the shift. Based on 2022 data, my previous article suggested that the new rule could increase scoring against Astros’ pitchers by 35 runs and increase Astros’ runs scored due to increased offense by 19 runs. In that article, I suggested that Alvarez, Tucker, and Bregman should be the most significant beneficiaries of the new shift rule. Of course, since that is based on last year’s data, it may not accurately predict what will happen this year.

Six games into the season, my impression based on watching the games is that the shift rule has helped Astros’ batters on occasion and also made Astros’ pitchers somewhat more hittable. Given the early stage of the season and resulting tiny sample size, I freely admit that this is simply an impression that isn’t much better than speculation.

At this point, we don’t have data directly tied to the shift. But we can examine ground ball and location/trajectory data. Although the shift can also prevent low-line drives, the most significant impact of the shift is on ground balls. Below I will review Batting Average on Balls in Play (BABIP) in the incipient 2023 season compared to the 2022 season. (Source: Baseball-Reference.com) This data is through 6 games.

BABIP FOR ASTROS’ PITCHING

Overall: 2023 .360 / 2022 (season) .269

Ground ball BABIP: 2023 .282 / 2022 (season) .228

LHB Pulled: 2023 .321 / 2022 (season) .267

Up the Middle-LHB: 2023 .400 / 2022 (season) .246

Up the Middle-RHB: 2023 .421 / 2022 (season) .242

BABIP FOR ASTROS OFFENSE

Overall: 2023 .295 / 2022 (season) .278

Ground ball BABIP: 2023 .281 / 2022 (season) .216

LHB Pulled: 2023 .375 / 2022 (season) .248

Up the Middle-LHB: 2023 .357 / 2022 (season) .299

Up the Middle-RHB: 2023 .246 / 2022 (season) .248

So, the take away from the comparison above:

• First, the overall BABIP for Astros’ pitching this early in the season is ridiculously high. This is a function of the small sample so far, and will surely regress at some point. The Astros’ pitchers have been unlucky on batted balls at this early stage of the 2023 season.
• Second, the ground ball BABIP for both Astros’ pitching and offense are elevated above 2022 levels, which is what we would expect if the shift rule is adding hits to the offense and decreasing pitching effectiveness. This doesn’t prove anything. But the 2023 GB BABIP is consistent with the shift rule and the direction it should change hitting stats. Maybe the comparison confirms my impression that the shift rule has significantly impacted so far.
• Third, the BABIP for LHB Pulled is also consistent with the shift rule affecting both the Astros hitting and pitching. The hitters who were most affected by the shift are LH batters (like Tucker and Alvarez). And we would expect pulled batted balls are affected the most, since the shift is designed to suppress pull hitting. We see a big increase in the BABIP for the Alvarez/Tucker pulled balls and a moderate increase in opponent LHBs when they pull the ball against Astros’ pitchers.
• Fourth, the BABIP for Up the Middle batted balls provides an interesting comparison. The shift rule prevents the shortstop and 2d baseman from positioning to the left or right (respectively) of the 2d base bag. Shifts previously allowed the infield to suppress hits up the middle. But it is harder to get to balls up the middle with the shift rule in place. On the pitching side, the Astros so far are getting burned severely by up-the-middle hits. However, Astros batters are not fully taking advantage of up-the-middle hits—at least to the extent that their opponents have. More specifically, the Astros’ LHBs have benefited from hitting the ball up the middle, but Astros’ RHBs have not.

The Astros’ pitchers have allowed a significantly higher BABIP on Line Drives (.732 vs. .595 in 2022). Since the shift can occasionally snag line drives, the shift rule may account for some of this increase. But I suspect that the pitchers have been allowing opposing batters to barrel up more balls, resulting in HRs. This may be due to poor BABIP luck.

Yes, this article is based on a super small sample size. But it does seem to support the idea that the shift rule has caused Astros’ pitchers to appear more hittable than we normally expect. And we also have seen Astros’ batters occasionally take advantage of the defensive limitation. Examining the early data indicates that Astros’ batters might be well advised to hit batted balls up the middle.