Three notes on the Astros as they travel to Seattle….
My article is called Astros Three Things when I cover a variety of brief topics related to the Astros.
- The Mariners series is important; how will it affect the Astros’ trajectory?
The Astros series in Seattle is important, if for no other reason due to the implications for the AL West race. It is early in the season, and we shouldn’t read too much into current games. But, by season end, the head-to-head series with the Mariners usually plays a significant role in deciding the AL West championship.
Will Sunday’s game against the Twins change how the Astros feel about themselves going into the Seattle series? The Astros scored eight straight runs to mount a comeback which they won in extra innings. Winning the series with the Twins also changes the Astros’ narrative, since the traditional mantra is “just keep winning series.” We can be optimistic, believing this will turn out to be a pivotal game for the Astros. However, the fact is we don’t know. Another traditional baseball saying: “Momentum is the next day’s starting pitcher.” And, well, the Mariners have great starting pitching.
In the early games of 2025, our focus has been on the offense which has been (to put it politely) “cold.” In addition to scoring a season high in runs, Sunday’s game could prove to be a turnaround game for several cold hitters who provided sparks for the sluggish offense. (Paredes, Alvarez, and Walker come to mind as low batting average hitters who broke through to varying degrees in the game.) One of the issues in the early season has been the ability to convert walks and hits into runs.
One of the best stats at evaluating this ability is a win probability stat: Run Expectancy 24 (RE24). Yes, due to sample size, we can’t make any strong conclusions about how players perform with respect to’ RE24. However, RE24 can provide us an indication how players have performed in the 24 base-out states in the early going. But it probably can’t tell us much about how players will perform in the future.
RE24 measures the value of a hit, walk, or out in each of the 24 base-out states. Unlike Win Probability Added (WPA), RE24 does not measure timing of leverage (i.e., inning and score), but relies on the base-out situation (e.g. bases loaded, 2 outs). Because RE24 is situational and considers factors like productive outs and base running, conceptually it is more informative of skill and repeatability than WPA. There are many base-out situations in which the batter may adjust his approach at the plate. RE24 is expressed as runs above average for that particular base-out situation. So, zero RE24 for a particular situation means that the batter’s impact on run expectancy in that situation is the same as MLB average for the particular base-out state.
Currently the Astros’ hitters with the highest RE24 are shown below.
Hitter/ RE24 runs above average
Paredes 3.51
Meyers 1.10
Altuve 0.39
Rodgers 0.03
Paredes had a great game on Sunday, that pushed him clearly into the RE24 lead. Smith, Waker, and Diaz are the bottom three in RE24. The Astros are ranked 27th in RE24, approximately 1.3 wins below average. So the team must continue improving the run expectancy numbers and move up the RE24 rankings. The Astros were ranked 9th in RE24 at the end of the season in 2024.
In January, I compared team over- or under- performance of RE24 with several offensive variables. I utilized BB-K as a proxy for hitter patience, and it proved to be the most important variable related to RE24 over/under performance. BABIP was the next most important stat for RE24; but it is a notoriously volatile batting stat, which is highly affected by random variation. It’s notable that the Astros are ranked 27th on BB-K, which is the same ranking as RE24.
A more direct measure of patience is pitcher per PA. Alvarez (4.51) . Paredes (4.38) . and Rodgers (4.0) are 1-2-3 on the Pitch/PA ranking of Astros’ hitters. Two of three are near the top of the Astros’ RE24 ranking. At a high level evaluation, Astros’ hitters should avoid an overreaction to their RE24 struggles and continue trying to achieve a more patient approach at the plate.
We will know more about the hitters’ trajectory after the Mariners series.
2. A Note on Yainer Diaz’s Framing
The advanced metrics last year indicated that Yainer Diaz’s pitch framing has some room for improvement (-7.9 runs in 2024, according to Statcast). So I found this analysis of “called strikes” by Tangotiger of some interest.
Tango analyzed all the catchers based on whether they crouched with knees up or down. You may have noticed the trend over recent years, with most catchers catching the ball with one knee up and one knee down. With only a few exceptions, he found that catchers were more likely to get called strikes when they had one knee up and one knee down. His Bluesky note below mentions Yainer Diaz:
tangotiger.com/index.php/si…
As he notes above, Yainer Diaz uses both knees up and one knee down about equally. But his called strike percent is much better with his left knee down (52%) than with both knees up (42%). Tango comments that he expects Yainer will eventually move to the better stance (left knee down). This is something to watch. Perhaps that move would improve his framing stats.
One thing not mentioned here—the one knee down posture may be detrimental to the catcher’s ability to avoid passed balls. At least that is what some announcers say. But Yainer’s stark difference in strike percentage probably has more value than avoiding a passed ball here and there.
3. Where are the torpedo bats?
The Astros have ordered torpedo bats, but they aren’t expected to “experiment” with them until they return home from Seattle. For those who haven’t followed the torpedo bat saga, the new bat design was the main baseball story early in the season after the Yankees had a couple of HR barrages, only to reveal that some of their batters were using the new bats. This riled up a lot of non-Yankees fans who were suspicious. (The torpedo bats are legal, as far as we know.) This led Commissioner Manfred to pronounce: “The torpedo bats are absolutely good for baseball.”
The torpedo bats have a different weight distribution than normal bats. It was designed by a physicist working for the Yankees. Some batters reportedly are uncomfortable swinging with a different bat weight distribution. However, some players find the new bats very helpful and have produced hard hit balls with them. Is the bat responsible for the higher production? Or is this some version of a placebo effect. I don’t know the answer.
My initial reaction was: Why are the Astros waiting until the end of this week to try out the torpedo bats? Why not the upcoming Seattle series? Admittedly my reaction is partly just fascination or curiosity about the new bats.
Tango reposted this comment from an analyst who made some assumptions and prepared an analysis of Jazz Chisholm’s torpedo bat vs. his normal bat.
So, in this example, if the ball is hit 2 inches below the sweet spot, the exit velocity increases from 94 mph with a normal bat to 98 mph with the new bat. That could result in a 162 point increase in wOBA. While that sounds promising, this is only one location on the bat. By that, I mean that the overall impact could be modest or nearly non existent when all batting events are taken into account.
Furthermore, the impact of the torpedo bat on vertical launch angle may be important, and I have not seen much discussion of that aspect. I’m not a physics expert, but my guess is that the usefulness of the new bat design may be a very individualized characteristic. The new design moves the sweet spot downward on the bat, and it may depend on where the batter normally hits the ball on the bat. So, maybe my initial reaction was not correct Perhaps the Astros first need to experiment and find out which batters would benefit from the bat. So, we will wait and see.