With nine games remaining, how well have the Astros’ performed lately? (And let’s give surprising kudos to Singleton.)
The Astros enjoy a very high probability of winning the AL West (98.4% according to Fangraphs and 99.7% according to Baseball Prospectus). With 9 games left in the season, let’s examine how the team’s performance has been trending this month. This may be relevant to how the Astros will perform over the next nine games, and also inform us about the momentum that the team carries into the playoff (assuming the Astros win the division).
To be clear, I don’t know that the performance over the last couple of weeks of the season (whether high or low level) creates any momentum (or lack of momentum) going into the playoffs. After all, players routinely say “It’s new season” when they enter the playoffs. But intuitively we understand why some people may think that short term trends at season-end tell us something about probable performance during the playoffs. In any event, teams really don’t want to test the hypothesis that “backing into the playoffs” foretells poor performance in the playoffs. Teams always prefer to be playing well when they enter the playoff bracket.
So, let’s look at recent trends in team offense and team pitching; in this case, looking at August and September. Because we are only 20 days into September, this is small sample size theater which can reverse at the drop of the hat.
Offense
I will focus on wRC+ which is a good measure of overall offense, and Isolated Power (ISO) which is a good measure of extra base power. The league ranking is shown in parentheses.
wRC+
Season / August / September
109 (7th) / 113 (9th) / 99 (12th)
ISO
Season / August / September
.154 (18th) / .161 (17th) / .128 (23rd)
The team offense has exhibited a down trend in September. This follows an August when the team offense was playing at its highest level, both in terms of wRC+ and ISO. The team ISO power (.128) is particularly weak in September, ranking 23rd in the league. Hopefully, this recent downward trend in the offense will regress in the direction of the seasonal average. The offense across the 2024 season has been above average and the offense during September has been below league average (wRC+). A return to August form would be even better.
With the offense trending down in recent weeks, we tend to notice poor sequencing more. This can be measured by the win probability “Clutch” statistic, which is based on performance relative to low, medium, or high leverage. The good news is that the Clutch ranking has been trending slightly upward on a team basis. The bad new is that the Astros are generally ranked poorly on Clutch offense.
Clutch Ranking
Season / August / September
29th / 26th / 20th
Pitching
Let’s examine both starting pitching and relief pitching. We will use ERA and SIERA as overall measures of run prevention. As above, league rankings are shown in parentheses.
Starting Pitchers
Season: ERA, SIERA / August ERA, SIERA/ September ERA, SIERA
3.84 (9th), 4.09 (19th) / 2.43 (1st), 3.26 (1st) / 3.80 (16th), 4.32 (24th)
Relief Pitchers
Season: ERA, SIERA / August ERA, SIERA/ September ERA, SIERA
3.50 (4th), 3.66 (12th) / 2.89 (3d) , .352 (8th) / 3.17 (11th), 3.22 (8th)
In terms of the starting rotation, August was truly an exemplary month. The Astros starters were ranked first in both ERA and SIERA. It’s not a surprise that the starting pitching regressed somewhat in September. The September rankings relative to the league fell to 16th and 24th for ERA and SIERA, respectively. Despite the poor ranking, the September starting pitcher results are similar to the overall season ERA and SIERA.
The relief pitching in both August and September is better than the season average. The ERA was ranked 3d in August, but the SIERA suggests that the ERA was over performing the peripherals in that month. The September relief ERA regressed somewhat and reduced the margin between ERA and SIERA. Overall, the relief pitching has performed fairly well in September.
Recent Player Performance
Based on the September performance to this point, the dip in offense is something to watch in the future. In order to examine the September offensive output, we can look at the wRC+ for Astros’ hitters in the month.
Fangraphs Leaderboard
I find it surprising that Singleton is at the top of the September leaderboard for the Astros. Chas McCormick is currently on the injured list, but there is an outside chance that he could return to active playing before the regular season ends. Tucker has not yet recovered his timing since returning from the IL and for now he is assigned frequent off days as he rounds into shape. Despite those drawbacks, Tucker’s wRC+ is pretty good; once he gets his batter timing back to normal, Tucker might be an even greater contributor in the future. Altuve and Alvarez have also been decent contributors this month. Despite that, Yordan Alvarez’s wRC+ is below his normal performance. Hopefully he will return to tremendous rate of output he exhibited in August. DFA pick up Jason Heyward has been surprisingly useful both on offense and defense.
Diaz, Bregman, and Pena have been slumping somewhat in September, and they are noticably below their norms this month. The downward trend in September will easily reverse if these three hitters return to their August performance level. The August wRC+ for Bregman, Diaz, and Pena was 167, 133, and 117 (respectively).
After reviewing these recent results, we should commend Jon Singleton in particular. Singleton is frequently viewed as one of the lineup’s weaknesses, but in the second half of the season he has proven to be a positive contributor. Singleton’s September slash line: .289/.341/.605 (OPS .946). During September, Singleton has contributed as much WAR as Alvarez and Tucker. Going back another month, Singleton’s August wRC+ was 121, which is more than respectable for a first baseman. Also during the second half of the season, Singleton has the highest Clutch rating on the Astros.
Todd Kalas brought up Singleton’s high RE 24 (Run Expectancy) during the Thursday game broadcast. Since RE24 is one of my favorite win probability stats, I was both surprised and pleased that they mentioned the run expectancy performance. RE24 demonstrates the extent that a player improves/decreases the team average run expectancy above/below league performance. It takes into account the factors which affect situational hitting. In the second half of the season, Singleton is 3d best on the team in RE24, behind only Alvarez, Diaz, and Altuve. Comparing Singleton’s RE24 to his wRAA suggests that his situational hitting is three times as productive as one would expect from his standard offensive stats. To sum things up, Singleton has been extremely useful to the Astros offense in recent weeks as well as the second half of the season.