Updating and expanding those month-by-month ERA charts posted awhile back...we'll figure out how to have them carry a bit more info by and by, but for now here's a quick read on the "range of perturbation" for starter and reliever units thus far in 2012.
Over in the Central, the Tigers have had a rough start from their starters in June, while the Royals are showing an uptick after a couple of rough months...the Twins are the only AL team with a 5+ ERA from their starters in all three months.
In the West, the Angels have gotten back into to the race thanks to a reversal in starting pitcher fortune with the Rangers.
The performance gap between starters and relievers seems to be approaching its apex in the AL, due mostly to a virtually-across-the-board surge from the bullpens. Five teams are currently sporting bullpen ERAs under 3. While there's still plenty of June left, the AL's collective 2.85 ERA is the lowest monthly value for the bullpen in twenty years.
Meanwhile, over in the NL, June is currently bringing forth a pitching resurgence from the Atlanta Braves [EDIT: those numbers will change somewhat after today's blowout loss to the Blue Jays], while the Cinderella story that is the Pittsburgh Pirates needs to address its declining starting pitcher performance lest their season get squashed by a pumpkin-like offense.
In the East, the Mets are trying to overcome a bad bullpen, while the Nats are settling into a nicely balanced performance from both staff segments. The Phillies are having a shocking June swoon from their starters (Roy Halladay is injured), and the Marlins are also on the hook.
The Reds have ridden their bullpen to the top of the NL Central, but like the Pirates their starting pitching has gotten balky thus far in June. The Cards' pitching came out hot in April, but has been struggling mightily ever since. The Brewers dug themselves a hole early, but they seem to turning things around. The young Astros pitchers have hit the wall hard in June, a trend that's likely to send them back toward the NL Central basement.
Coors Field is moving back in the direction of its so-called "glory days"--it appears that the humidor needs some kind of overhaul. The Dodgers and Giants have, for the time being at least, rendered the NL West into a two team race, with only the D-Backs looking as though they've got a shot to pull together enough pitching to regain some traction.
We're not seeing nearly as much difference between starter and reliever performance in the NL, which leads to the quaint notion that an outsized portion of the ostensible reason why the AL is a "superior" league (a neo-sabe core concept for the past few years...) is due to having better relievers. Given the level of importance that relievers are usually assigned in the run-win models, that's nothing more or less than a kick in the head--or, possibly, a blow aimed a good bit lower.
We'll check back on this around the All-Star Break...