Let me just say, as a Cardinal fan, I fully support and endorse this move.
Seriously, this has to be one of the most asinine moves I can recall in recent years. Lou Piniella has just managed to turn an $18 million dollar pitcher into a glorified middle reliever. Zambrano is going to be used as a setup man, which at least means he may pitch in high leverage situations, but there's absolutely no way a setup man will ever, ever, ever be worth what they're paying Zambrano. They're paying him to be a four win player; Mariano Rivera has never been worth more than 3.2 wins in a season since we began tracking WAR, and he's the greatest closer who has ever lived. Trust me when I say Zambrano isn't going to get close to four wins as a setup man.
More importantly, the move to the bullpen isn't really even warranted, as Zambrano hasn't actually been terrible this season. Sure, that 7.45 ERA looks ugly, but there's a whole lot more to the story than just that number. That ERA is largely a product of Z's implosion on Opening Day, when he gave up eight runs in just an inning and a third. Since that disastrous outing, Zambrano is 1-1 with a 4.00 ERA and 25(!) strikeouts in just 18 innings. Now, I'm certainly not claiming to have the genius baseball mind of Lou Piniella, but those numbers don't look to me like the sort that desperately cry out for a demotion to the 'pen.
The fact is, Zambrano has actually been pretty good since shitting the bed on Opening Day. That strikeout rate alone is proof he's doing something right; hitters are apparently having a hell of a time making contact on whatever he's throwing up there.
There are two reasons Big Z's numbers look so ugly: his batting average on balls in play and the rate at which he's giving up home runs. His BABIP is .435, which will come down closer to normal levels as the season goes on. (Admittedly, he has given up a high percentage of line drives this season so far, which would account for the high BABIP, but I would expect that to come back toward his career norms.) The other issue is that 21.1% of the fly balls Zambrano has allowed this year have left the ballpark. Again, that's just not a sustainable rate. When those two numbers begin to come back to Zambrano's usual range, he's going to be the exact same pitcher he's always been, and the Cubs are going to have the biggest waste of a resource in all of baseball.
The bottom line is this: Carlos Zambrano may not be the ace he looked to be for a couple years, when the Cubs mistakenly thought he would somehow be worth nearly 20 million a year until the end of time, but he's still a remarkably consistent performer. He's never posted an ERA above 4.00 in any full season in his career. He's never thrown less than 169 innings in a season since becoming a full-time starter in 2003. In short, Carlos Zambrano is a huge asset to a team, much as it pains me to say so. (No, he's not worth the money, but that's really a separate issue entirely.) And now the Cubs are going to use him to throw 3-4 relief innings a week while Carlos Silva ticks his way toward self-destruction as part of their rotation.
Like I said, as a Cardinal fan, I'll take any chance I can get not to have to see Zambrano starting games against my team. So go ahead, Lou. Use your $18 million setup man however you like, and wonder why your team just doesn't seem to be able to get any traction.
I would also, as much as I've always hated Zambrano, be willing to toss you guys a middling prospect (or Kyle Lohse!), if you'd like to trade him our way and pay most of his salary.
