The old adage stated that 500 minor league innings was the floor that teams should allow their pitchers to reach before debuting them at the big league level. Doing a rough research session of the past two seasons' ERA qualifiers and their minor league innings, here's what I've established:
- 152 pitchers qualified for the ERA crown over 2006/2007.
- Of those 66 had 500 or more minor league innings, and 87 had 450 or more innings.
- 6 of the top 10 ERA leaders qualified for a part of the 87, Roy Oswalt and John Lackey being the top representatives.
On the X axis we see the ERAs from the previous two seasons, on the Y axis we have the amount of minor league innings thrown. There's no clear correlation, but I decided to try one more stat run. My theory was the more more league innings thrown the fewer walks a pitcher would give up.
As it turns out that hunch also has little correlation to support it, despite my previous idea that the longer a pitcher spent in the minors the more refined he could become and the higher to his full potential he'd reach. When I talked about the Rays and James Shields/Andrew Sonnanstine developing better pitches it seems those cases are more isolated than I would've imagine and minor league innings really don't tell us much, instead we should use a pitcher-by-pitcher basis for each situation.