The Cratering of a Pitching Staff

It's certainly not a surprise to anyone following the team that our starting pitching over the past month has been "suspect," to put it politely, fueling the recent calls for trades.  But how suspect?  

• Manny Parra: since whittling his ERA down to a Suppanian 4.57 on May 17, Parra had since given up an astounding 31 earned runs in his next 21 1/3 innings, raising his ERA almost 3 full runs in only 5 starts.  Wow.  Parra is currently on a sabbatical in Nashville.
• Braden Looper: it's hard to imagine that Looper had a 2.45 ERA in April (THAT seems a long time ago), and a 4.24 ERA as late as May 29.  Since then?  18 earned runs in 20 1/3 innings, raising his ERA just about 1 full run.  (Oddly enough, his strikeout : walk ratio in that time period is a nifty 16:2 --- why take a walk when you can hit for extra bases, I guess.)
• Dave Bush: on May 19th, his ERA was a fantastic 3.74.  Since then?  Well...29 earned runs in 28 innings, raising his ERA almost 2 full runs.  It's worth noting that he's attributed his recent slide to getting hit by a line drive in Florida on June 4th, even though by then his ERA was already on the way back up, having given up 9 earned runs in his previous 10 2/3 innings.
• Jeff Suppan: remarkably, perhaps reveling in the misfortune of his staffmates, Suppan's ERA has been trickling downward: his current ERA, 4.48, is as low as its been all season, and he hasn't given up any home runs in June.  That's all fine, of course, when Suppan is your #4/5 guy.  When he's your best starter not named Gallardo...hoo boy.
• Yovani Gallardo: Gallardo is still doing fine, of course, and his ERA is back under 3, something we haven't seen since April.  The only thing of concern to me is the innings pitched: in only 2 of his last 7 starts has YoGa gotten out of even the 6th inning.  He's still pitching well, but not offering our overtaxed bullpen a break.

To put it another way:

Our relievers have been performing admirably all season, but that's not going to continue if we keep asking them to pitch 3+ innings every night.  Landing another starting pitcher would be helpful, if Billy Castro can get Looper and Bush turned around and if Gallardo and Suppan are able to keep us in games without killing our bullpen. However, when your 2, 3, and 4 starters all collapse at the same time, it's hard to see how someone like Doug Davis will get us into the playoffs.

*Since May 20, the Brewers have gone 12-17, and as of this writing have fallen into second place.