Going in a different direction today, as we look at the reasons why Houston is now 16-14 in its last 30 games...
1) The pitching
A big reason for Houston's continued success in the last month has been the pitching staff. Last night on the podcast, I talked about how Paul Clemens was the only pitcher on the roster right now who had negative fWAR for that timeframe. Since then, Jose Veras has joined the list.
Still, Houston pitchers have been lights-out and much better lately than they were at the beginning of the season. Bud Norris and Erik Bedard lead the way with 67 combined innings and 1.6 fWAR between them. Mike Fast chimed in on just this fact last night on Twitter.
Best pitching staffs in MLB over last 3 wks: KC 2.9 runs allowed/gm, Oak 2.9, Det 3.1, Astros 3.2. Great job by Brocail, Martinez, and team!— Mike Fast (@fastballs) June 17, 2013
It's no surprise that a big reason for that success has been the starting rotation. Gone are the days where Houston's starting pitchers couldn't get out of the first inning. Now, every one of them has an ERA under 4.00 for the last 30 days and has thrown at least 32 innings.
The offense has been pretty much the same as ever lately, dropping slightly in runs per game, but the pitching staff has been able to shave off over two runs from what it was allowing at the beginning of the season. That's a huge reason for Houston's success lately.
2) Jason Castro
Like I said, the offense has been about the same, if a little worse in the last 30 days. But, one guy has saved it from being pretty bad.
That's right, he's your probable All-Star, catcher Jason Castro. In his last 100 plate appearances, Castro has hit .322/.400/.644 with seven home runs, a stolen base, a weighted On-Base Average of .435 and a wRC+ of 182. He's been walking at a 12 percent clip and striking out 22 percent of the time. His isolated power average is an incredible .322.
All that adds up to him being worth 1.5 fWAR over that span, which is 1.2 more than anyone else on the team. Castro has been average in both fielding and baserunning components of WAR, so all that value is tied to his bat.
Did I mention he's barreling towards a 20-homer season behind the plate for Houston? As we've talked about before, the team record for homers by a catcher is 17 by Mr. John Bateman. Castro is already ninth on that list with his 10 homers to this point, so there's a good bet he'll get close to taking the title for himself.
3) Run differential
Finally, let's discuss how many runs Houston is scoring and how many they're giving up. One of the more interesting sabermetric concepts is that runs are a better predictor of future win totals than actual record. That's why teams with negative run differentials are viewed skeptically, even if they might maintain that for an entire season.
Houston has been super-bad in run differential. Like -100 runs bad. But, over the last 30 games, the Astros have scored 107 runs and given up 112 for a run differential of -5. It's not great, but it does show that Houston has been legitimately playing like a team around .500 for that stretch.
The big drop has been in runs allowed, like we talked about above. Houston averaged 3.73 runs per game given up over that stretch and have given up 5.14 runs per game for the season. Before this stretch, though, Houston was giving up 6.2 runs per game, so they've almost dropped that total by 2.5 runs.
Even more encouraging is that Houston is closer to being even in run differential for the month of June, as Houston has scored 45 runs and given up 48 in 15 games this month. That's a sign of progress and a sign that this team might not be historically bad after all.