I Don't Get It

With Rich Harden coming back the A's - get this - have too much starting pitching. They are stuck with 6 decent starters, which is why they have the 3rd best record in the American league, despite a no-name clubhouse. How do they manage to develop young pitchers like this? How do they get a Cy Young for Barry Zito and with the Giant's he's gonna lose 20 games this year? Can someone explain this?