I made a post tonight at BTB concerning the correlation between baserunners per nine and ERA, to sample it:
This is based on nearly 1,000 cases since 1999. Essentially it's baserunners per nine rankings of pitchers with at least 150 innings in that season and the correlation to their ERA. I included pitchers with at least 40 innings thus far this year to get closer to 1,000. What the correlation shows us is that this can tell us to a pretty decent degree what an ERA SHOULD be.
For those a bit unfamiliar with how to plug the numbers in just follow the formula at the top right of the image [.4902*(baserunners9) - 1.7145] and we'll get a "projected ERA".
Taking the formula I plugged in each of our pitchers to see who's lucky and who's not thus far:
Take from this what you may, but it suggests that Reyes/Percy have been the most unlucky, and that Garza and Glover have actually been lucky, ew.