In winning their rubber match against the Indians on Sunday night (HOU 3, CLE 1), the Astros limited Cleveland to a single run (starter Lance McCullers worked seven scoreless and allowed only one hit). Such a paltry tally for the opposition is of course nothing new for the reigning champs this season. Consider ... 

  • Houston has now played 48 games this season, and in 20 of those it has allowed the opposition to score one run or zero runs.
  • Framed another way, Houston has allowed more than three runs in a game just 14 times this season. 
  • In matters very much related, the Astros now have a team ERA of 2.43. That leads the majors by a wide margin. Second is the Cubs with a mark of 3.28. Second in the AL is the Red Sox with a mark of 3.60. 
  • If that 2.43 team ERA holds up -- unlikely, but just go with it -- then it would be the lowest team ERA since the 1919 Cubs put up an ERA of 2.21.
  • That was almost a century ago, and that was of course the Deadball Era. To put that in context, teams in 1919 averaged 3.9 runs scored per game. Thus far in 2018, AL teams are averaging 4.57 runs per game. The 2018 Astros are putting up their ERA in a vastly tougher environment. 

What's also striking is that the Houston rotation this season is now running an ERA of 2.25. Even if you take into account the team's trade for Gerrit Cole and having Justin Verlander from Opening Day onward, that's an absurd figure. Just five Houston pitchers have made starts this season, and of those Dallas Keuchel has the worst ERA at 3.43. Another fun fact: You can add Verlander's and Cole's ERAs together, and the resulting figure is still lower than Jake Arrieta's current ERA (2.82, which is top 10 in the NL). 

To be sure, a strong fielding corps has also helped Houston keep the runs allowed down. Right now, the Astros lead all of baseball with a .730 defensive efficiency, which is the percentage of batted balls that a defense converts into outs. The work of Houston's fielders is partly reflected in all those numbers above. To reign in all components more fully, let's look at runs allowed ... 

  • The Astros have presently allowed 123 runs -- the fewest in all of baseball. 
  • The Diamondbacks are second with 164 runs allowed. In the DH league, the Yankees and Red Sox are next with 178 runs allowed. There's leading a category, and then there's owning it. The Astros are doing the latter. 
  • The Astros are on pace to allow just 415 runs for the whole season. 
  • If that holds up (it probably won't), that would be the lowest tally in a season not shorted by labor strife since ... the 1919 Reds gave up 401. Yes, there's that Deadball Era again. Of course, those 1919 Reds played just 130 games. The Astros are on pace to allow 415 over 162 games. 
  • And that -- those 415 runs -- would be the fewest ever allowed by a team to play at least 162 games in a regular season. 
  • To find a team that played in at least 150 games and gave up fewer than 415 runs, you must go back to the 1909 Cubs. 

The likely reality is that Houston won't be able to keep up this pace, which is the case with almost any outlying performance. That said, remove defense and luck from the equation, and Houston pitchers have still thrived. FIP (Fielding Independent Pitching) is scaled to look like ERA but reflects just those outcomes that have nothing to do with fielding -- i.e., strikeouts, walks and home runs allowed. The Astros right now boast a sub-3.00 FIP, and they're more than half a run better than the next team in line. In other words, although the Astros are likely to regress at some point, they might not regress as much as you'd think -- assuming they stay mostly healthy. And they've already built this statistical foundation, which will be reflected in whatever the final numbers are. 

Speaking of which ... 

The 1968 season was of course the Year of the Pitcher, which led to the mound being lowered. 

Whatever happens the rest of the way, Houston's run prevention has been legendary thus far. It's still somewhat early, yes, but we could be looking at one of the great pitching-and-defense teams in the history of the game.