The Astros face a slow grind to erase an early season power problem
We all know that the Astros’ offense has struggled so far this season. Yes, it’s a small sample and not predictive of the future. (A good thing too.) However, the most daunting offensive problem has been a lack of power.
Let’s look at the Astros’ offensive power rankings as of today vs. 2024.
MLB Offense Ranking: Today / 2024
- SLG 25 / 8
- ISO 26 / 15
- HR 27 / 10
The Astros currently rank close to the bottom in SLG, Isolated Power (ISO) and home runs. Last year the Astros were top 10 in slugging and home runs, and they were middle of the pack in ISO. If the Astros’ offense will perform like we expected, the team needs to make gradual and definite improvement in the power department. The gradual improvement in overall output is likely to occur, but we don’t know the timing. Given the small improvement recently, perhaps the power trend has begun: over the last 7 days, the Astros are ranked 13th in SLG and 15th in ISO. We don’t know if that is a blip or the beginning of a sustained improved power output.
Given the small sample size to this point in the season, the x-stats (expected stats) at Baseball Savant can provide important insight as to whether the current power stats reflect good or bad luck. Below are the Astros’ hitters actual SLG so far versus expected slugging (x-SLG). A negative difference indicates that x-SLG is higher than the actual SLG. The x-SLG statistic can indicate whether the actual SLG stat should be higher or lower based on the results expected from the quality of contact and defense against the batted balls.
Baseball Savant
- The majority of Astros’ hitters have been unlucky in slugging. Only Paredes, Altuve, Smith, and McCormick have a x-SLG below the actual slugging.
- The Savant data above was downloaded before Tuesday’s game. The current Top 5 in x-SLG based on 4-30-25 data: Alvarez (.502), Pena (.450), Diaz (.415), Walker (.403), and Caratini (.380). Compare those x-SLG numbers to the table above and you can see how much difference one game can make at this stage of the season (particularly for Walker).
- I calculated the Astros team SLG and x-SLG based upon the weighted average of hitters’ balls put in play. The Astros’ weighted average SLG is .352 and x-SLG is .397. The x-SLG is .045 below the actual SLG. This indicates that the Astros’ overall SLG stat is somewhat unlucky.
- For whatever reason, the Savant data indicates that MLB league average x-SLG is .028 above actual SLG. This differential may exist on a league wide basis for any number of reasons, including random variation and improved defensive performance. But the Astros’ data suggests that the difference in the team’s x-SLG and SLG is more than twice the league average.
To the extent that the Astros’ slugging has reflected bad luck so far this season, this could be a good sign for the team’s power going forward. One would expect future regression to cancel out some of the bad luck on the power side. That is to say the future “rest of season” (ROS) SLG number should regress toward the mean.
Current (today’s) Savant x-SLG indicates that the expected big HR hitters (Alvarez, Diaz, Walker) in the lineup should have a SLG more than 100 points higher. This is an encouraging sign that the team’s power numbers should improve significantly over the rest of the season, This is particularly true if unexpected sources of power like Pena (x-SLG 60 points higher than SLG) and Rodgers (x-SLG 65 points higher than SLG) also improve along the lines of their x-SLG.
The Fangraphs batting projections, in fact, anticipate improved power over the remainder of the season. For example, Steamer’s ROS HR totals for specific Astros hitters: Walker (24), Alvarez (27), Altuve (18), Paredes (20), and Diaz (16). Only time will tell if the projections prove to be reasonable.
If and when the Atros’ offensive power reaches original expectations, and assuming that the pitching stays close to its current performance, the Astros’ winning percent should climb considerably.