Now here are some charts that we haven't seen anywhere else...
These depict the inning-by-inning earned run averages (ERA) for the thirty MLB teams. The first is the raw ERA; the second is ERA+ (with a little added enhancement).
It's more of the materials that are possible to break out at Forman et fil utilizing their (relatively) new "Split Finder" tools in their Play Index.
We can see how the relief pitchers take over in the seventh; ERA progressively improves; by the ninth, the overall ERA is almost exactly a run lower than it is in the first.
This has prompted a number of theorists, a large group of which have been known to consume liberal portions of what we like to call the Tango Love Pie™, to push for a sizeable increase in the use of the relief pitcher at an earlier point in the game.
What we'd like to see Sean F. devise, however, is an output that breaks out inning-by-inning ERA in a way that separates starting pitching from relief pitching. We think it's likely that the relievers in the sixth inning aren't quite so wonderful, primarily for the reason that they're not quite as accomplished at pitching as the top-shelf relievers.
We've also combined innings in the summaries at the right of this chart. Interesting to note how well the Cubs' starters pitch in the first three innings--second only to the Pirates--but how they fade away as the game goes on. (They have a downright lousy bullpen.) The Braves have a great second wind in the latter part of the game--their "transitional performance" in innings 6-8 just blows everyone away and is clearly a key aspect of their success in the NL East this year.
Please also note that our bolded figure in the ninth inning, intended to highlight the best team performance (primarily the closer), is wrong. While the Royals have had a wonderful performance in this inning (largely due to the yeoman work of Greg Holland), it's actually been the Oakland A's who've been the best in the ninth inning thus far in 2013.
Interesting to note as well that there are two teams who start out below average in innings 1-3 but who diverge from there, with the result that they are in radically different locations in the standings. Those two clubs? The Rays and the Astros.
We'll have to go back and look at this data for 2012, but we're guessing that the San Francisco Giants have had a significant performance downturn from their starters over the first three innings of games in 2013.
All in all, a set of numbers worth taking a look at. We still want to see the starter-reliever breakouts, particularly for the sixth and seventh inning, but this is nice stuff.