This thread: http://www.whatifsports.com/forums/Posts.aspx?topicID=435942&page=1
inspired me to run a series of tests on pitchers with low BB and K rates and pitching them at lower fatigue fatigue levels. I'm still running these tests, but I have enough data now, that I feel I can post something. I've run three teams in an OL with the goal of having my pitchers pitch down to 80%.
I have very carefully selected pitchers that have low BB and K rates to see if their performance is effected much by fatigue (I expect their K rate to drop and BB rate to increase, but giving the low starting points of each, even a substantial % change will have a minimal real world effect; i.e., a 50% increase in BB rate for a pitcher with a 0.78 BB/9 will only see a 1.12 BB/9, which is still excellent, though significantly worse percentage-wise).
So, the pitchers I chose for this test were as follows:
1909 Addie Joss
1996 Kevin Brown
1997 Greg Maddux/1922 Babe Adams
1902 Bill Bernhard/1919 Slim Sallee
1918 Fred Toney
1918 Jake Northrop
1991 Dennis Rasmussen/ 2012 Koji Uehara
1938 Dizzy Dean/1950 Joe Ostrowski/1924 Babe Adams
1988 Bob Milacki/1972 Chris Zachary
After the first test, it became clear I didn't quite have enough IP to get solid data as several of the pitchers were pitching down to the 50% range. So, I swapped out Sallee for Bernhard, Adams for Maddux and Ostrowski (and Dizzy Dean), and MIlacki for Zachary.
I'll only be focusing on the starters, Toney, and Northrup for now as I have more data on them than the others. Each has appeared on at least two teams and has at least 80 games pitched worth of data. In order of data: