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Recent Pitching Decline, How much of a Concern? Astros Trending May 31-June 6

Last week we noticed this decline and asked if it is a blip or a trend. Could be a trend. Should the Astros worry?

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MLB: Boston Red Sox at Houston Astros Troy Taormina-USA TODAY Sports

Note: I have decided to change the format of this column by leading with a discussion of the main trend. Weekly statistics follow.)

In the first installment of Astros Trending we were out front noting not only the lead that the Astros pitching staff had on all others in the league in just about every meaningful category, but how if those trends continued the Astros pitching staff would be remembered as one of the best in all history. For example, we noted that the staff ERA+ of 163, meaning the team ERA was 63% better than league average, was not only the best in history, but if it continued throughout the season, would smash the previous record of 131.

As I write, the Astros ERA+ is now 133.

We cautioned that regression was likely, but it has hit harder and faster than most would have expected. Below is a chart showing the ERA of the Astros pitching staff as a whole as well as its individual members before and after May 26, a major watershed in which the Cleveland Indians broke through against the Astros with 8 runs. In the ten game stretch since then the Astros have surrendered 5 or more runs in seven of those games.

Astros ERA Stats. Before and After

Team/Player ERA Before May 25 ERA Since May 25 ERA Season
Team/Player ERA Before May 25 ERA Since May 25 ERA Season
All Astros 2.38/1st 5.44/25th 2.89/1st
Justin Verlander 1.08 2.13 1.24
Collin McHugh 0.46 3.52 1.32
Hector Rondon 2.04 0 1.74
Chris Devenski 1.45 4.5 1.99
Gerrit Cole 1.86 3.86 2.2
Brad Peacock 1.83 6.23 2.63
Charlie Morton 2.04 7.15 2.84
Tony Sipp 3.72 0 2.84
Lance McCullers 3.2 7.84 3.89
Dallas Keuchel 3.39 8.49 4.13
Will Harris 3.12 15 4.87
Ken Giles 3.38 15 5.12
Joe Smith 6.91 0 5.21

Here are a few takeaways from this data.

Obviously in the last ten games the Astros gave up almost twice as many runs per game as they did in all the games before May 25th. From being the best staff in baseball with no close rival they have become almost the worst in the last ten games in terms of runs allowed. Their season ERA still leads the league, but in only ten games it has gone up a half run a game. How far will this trend go?

Of course it goes without saying that this Astros team, almost the opposite of last year’s, is predicated on superior pitching. Not surprisingly the Astros lost 7 of the 10 games they played in this stretch, and the only ones they won were the three in which the staff held the opponent to 3 or fewer runs.

Who is to blame? Almost everybody. Even Justin Verlander is giving up twice as many runs during this stretch as he was before. Of course 2 Xs very little is still pretty small. He’s still the rock. Gerrit Cole’s ERA in this period is approaching 4. And that’s the good news. Charlie Morton’s ERA during this time is about 7. Lance McCullers is near 8. Dallas Keuchel is near 8.5. Their season ERA’s have all climbed accordingly.

All the major cornerstones of the bullpen have seen major declines as well, some of them disastrous. Yeah, I’m looking at you Ken Giles and Will Harris. Oddly, some of the relievers generally perceived as lower leverage guys have alone been perfect during this time, albeit in limited use. (Tony Sipp, Joe Smith, Hector Rondon)

How to interpret this slump? Some would be inclined to say it is meaningless and all will return to amazing soon. Others will tend to say that a 5.44 team ERA is the new normal and we should all stock our bomb shelters with fresh MRE’s.

Well, I believe that this pitching decline does mean something, that in many ways it was predictable, and that the Astros staff will probably not quite return to its earlier pace or end up as the GOAT. On the other hand, just as the staff may have benefited from some good luck earlier in the year, it has had some bad luck of late, and that in the end it will still be the best staff in baseball.

Below is another set of statistics, some of which amplify the pitching decline of the past 10 games, showing before and after WOBA statistics for the team and for the players individually. Predictably, those pitchers who showed the highest increases in ERA had the highest increases in WOBA against.

I included the statistics for all the players for stat geeks who love that sort of thing, but what I want to discuss are the team predictive analytics, the Statcast xWOBA, FIP and xFIP, and try to glean what they have to say about the future of Astros pitching.


Team/Player WOBA Before May 25 WOBA Since May 25 WOBA Season xWOBA FIP xFIP Season ERA
Team/Player WOBA Before May 25 WOBA Since May 25 WOBA Season xWOBA FIP xFIP Season ERA
All Astros 0.255 0.332 0.267 0.289 3.1 3.17 2.89
Justin Verlander 0.201 0.215 0.203 0.231 2.2 3.5 1.24
Collin McHugh 0.227 0.302 0.246 0.316 2.11 2.72 1.32
Hector Rondon 0.275 0.205 0.263 0.302 2 2.94 1.74
Chris Devenski 0.239 0.368 0.263 0.244 2.76 2.9 1.99
Gerrit Cole 0.233 0.282 0.239 0.267 2.55 2.61 2.2
Brad Peacock 0.244 0.445 0.283 0.295 3.82 2.67 2.63
Charlie Morton 0.253 0.451 0.286 0.284 3.66 2.84 2.84
Tony Sipp 0.301 0.098 0.263 0.298 2.56 3.97 2.84
Lance McCullers 0.272 0.367 0.285 0.313 3.46 3.5 3.89
Dallas Keuchel 0.298 0.357 0.304 0.315 4.3 3.64 4.13
Will Harris 0.251 0.494 0.292 0.316 3.21 3.05 4.87
Ken Giles 0.262 0.47 0.306 0.362 2.06 3.26 5.21
Joe Smith 0.35 0.046 0.285 0.307 4.01 3.49 5.21

Predictably, the Astros staff led the league in their early season stretch, and still lead the league, in Weighted On Base Average. In the last ten games they were 18th.

xWOBA is a predictive statistic created by Statcast which takes all batted ball data on a pitcher and projects his future WOBA against. Currently the Astros pitchers have a WOBA of .267. This WOBA produced their season ERA of 2.89. Statcast expects the WOBA (xWOBA) to increase to .289. This would of course add to the current ERA. However, it is a great deal below the .332 WOBA of the last 10 games, which tells us that the 5.44 ERA of the period will not be sustained either.

Statcast’s xWOBA projects that the Astros will have the lowest WOBA in baseball, ahead of the 2nd place Dodgers.

FIP is a statistic that takes fielding out of the pitching equation and is designed to predict ERA. xFIP does the same but tries to take home run luck out of the equation as well. Currently these statistics predict that the Astros’ ERA will stabilize around 3.10, above the current level but nowhere near as high as the last 10 games.

Even during the hot streak when the team ERA was 2.38, xFIP predicted an ERA of 3.15, meaning that the Astros were having home run luck during that time.

They had other luck as well. When the team ERA was at .238, the Astros had the highest percentage of runners left on base at 81.8%. They also had the lowest BABIP (batting average of balls in play) at .263.

In the last ten games, the left on base percentage is 69.6%, 23rd in the league, and BABIP is .301, 17th. That’s for a team that leads the league in Defense Efficiency Ratio.

Another predictive pitching metric, SIERA, also designed to replicate and predict ERA, has the Astros staff at 3.09.

Pessimists might object that using predictive statistics for the whole season gives too much weight to the performance of the staff when they were pitching well, and is therefore unfairly biased against the less optimistic thesis that the bad pitching is a new normal.

Taking that into account, FIP and xFIP from the 10 game bad period predicts that, if that performance were to continue for the whole year, the Astros ERA would be 4.56 by FIP, but 3.31 by xFIP, far below the 5.44 ERA of that period. Which indicates that just as the pitchers were benefiting from good home run luck during the early season, they have been suffering from bad luck during this 10 game drought.

Applying FIP and xFIP to some of the individual pitchers we should expect some regression from most of the staff, significant regression from Verlander, McHugh, and Devenski but improvement from Harris, Smith and Giles. On the other hand Giles’ xWOBA is by far the worst on the Astros and near the bottom of the league.

It should be noted that during the fat times the Astros were pitching mostly against a relatively light schedule. During the ten game horror show the Astros were facing the three best hitting American league opponents, the Yankees, the Red Sox, and the Indians. Obviously this accounts for some of the increased run production against the Astros during this time. But of course, these are the teams the Astros need to beat.

So should Astros fans be concerned about the recent decline in pitching?

This recent stretch IS the regression that was predictable and predicted. The staff will pitch better, probably not as well in terms of results as earlier, but will still probably lead the league in ERA by the end of the year if the statistics used to predict these things have any validity.

This situation is however problematic, because the perceived advantage the Astros have had thus far has been based on an overwhelming superiority in pitching that was enough to overcome the superior hitting of the team’s two strongest rivals. Going forward the Astros staff will probably not get as many 0, 1, or 2 run games percentage wise as they did in the early season, the kind of performances that contributed so much to their early success. If so, the hitting will need to perform a little more like it did last year to compensate.

(Note: this was written before last night’s game. The Astros’ gave up five runs, but scored seven. This should be the template going forward. McCullers’ ERA is now 3.94, up slighlty from the 3.89 posted above.)

The Week in Review: May 31-June 6

Season Record: 38-25, Second in AL West, 1 game behind the Seattle Mariners. Fourth in AL behind the Red Sox, Yankees and Mariners.

Pythagorean won/loss record: 45-18, best in MLB. Run differential: +118

Baseball Reference SRS: 2.0, best in MLB

Week Record: 3-3 The Astros came home from a tough road trip to Cleveland and New York, but were still in the middle of the gauntlet, confronting the AL East leading Boston Red Sox for four and the AL West leading Mariners for a short two game series. The Astros split both series.

Season Hitting: The Astros are currently rated fourth in batting in ML with a 108 WRC+, the same ranking as last week but one point higher. They trail the Yankees by 9 points and the Red Sox by 6. Last year the Astros’ WRC+ was in the mid 120’s. They are fourth in runs scored at 309, 12th in home runs at 72, and 5th in batting average at .258. The Astros are 6th in OPS at .748, two points higher than last week and one ranking higher.

Currently Jose Altuve leads the team in BA at .332, George Springer in home runs with 13, Carlos Correa leads in RBI with 39, Springer is the OPS leader at .875, and Jose Altuve leads in stolen bases with 8.

Last Week’s Batting: The Astros continued hitting at about the same pace as last week, with a 116 WRC+, one point higher than last weeks score, and ninth in MLB, just behind the Yankees for the week and just ahead of Mookie Betts-less Red Sox. The Astros were 12th in OPS, at .773, 16th in runs at 26, (they allowed 31) and 14th in home runs at 7. Below are individual statistics for all position players last week.

For comparison purposes here are individual Astros hitting and pitching statistics for the season.

Who’s Hot: After about two weeks in the freezer, its good to see Carlos Correa swinging it again, with two home runs and a .946 weekly OPS. But George Springer gets top honors with a 1.280 OPS for the week. Tony Kemp keeps getting on base, with three bigs hits last night. Evan Gattis has continued to swing his home run bat, adding two more last week. Yuli Gurriel and Alex Bregman led the team with 5 RBI.

Who’s Not: After returning from Fresno last week with a big home run in New York, J.D. Davis has had some bad BABIP luck in his second week back. Max Stassi has returned to Earth now that he has the starters’ role at catcher with Brian McCann on the DL.

Pitching: Since pitching already dominated the discussion on weekly trends I will limit further discussion here. Below is a table with the up to date statistics for the last week only, including last night. Previous discussion did not include last night and went back to May 26th.

Justin Verlander still leads MLB in ERA at 1.24. Gerrit Cole is fourth in the AL at 2.20 and despite his blowout against Boston, Charlie Morton is still seventh at 2.84. Gone is the time when the top thee pitchers all had ERA’s below 2.

Gerrit Cole still leads the AL in strikeouts at 116, Verlander is third at 104, and Morton is eighth at 92.

Justin Verlander, Charlie Morton amd Lance McCullers each lead the team in wins, stuck at 7. Ken Giles leads the Astros in saves with 10, and Chris Devenski leads in holds with 11.

AS a team for the season the Astros continue to lead MLB in ERA at 2.90, WOBA at .271, strikeouts at 646,, BA at .208, K/9 at 10.3, WHIP at 1.04, FIP at 3.16 and xFIP at 3.19.

AS explained earlier these league leading numbers are down from just 11 days ago, when ERA was .238, WOBA was .256, BA against was .186, WHIP was .938. Still the Astros lead the league in pitching in an impressive fashion. ERA+ is now 133 as of today, just a smidge above the modern all- time record.

Fielding: The Astros still lead the league in FPCT (.992) and Defense Efficiency Ratio (.723). Carlos Correa has continued his streak of errorless fielding and is more than half way to the record of most consecutive games without an error by a shortstop: 110. The least errors by a shortstop in a season is 3, a record held by Cal Ripkin.


Who was this week’s most valuable Astro?

This poll is closed

  • 10%
    Jose Altuve
    (17 votes)
  • 1%
    Carlos Correa
    (3 votes)
  • 38%
    Evan Gattis
    (60 votes)
  • 10%
    Tony Kemp
    (16 votes)
  • 23%
    George Springer
    (37 votes)
  • 5%
    Tony Sipp
    (9 votes)
  • 5%
    Yuli Gurriel
    (9 votes)
  • 3%
    Alex Bregman
    (5 votes)
156 votes total Vote Now