"No matter how pitching is evaluated and what rates are factored into a metric you're still going to end up having to explain my least favorite concept in modern sabermetrics, luck." When sabermetric talks about luck, they are referring to statistical uncertainty. Statistical uncertainty is not a "concept of modern sabermetrics". It is an indisputable fact of probability statistics. Everything we observe in baseball is the sum of the signal (true talent) and noise (luck). Anyone who claims the signal or noise in any situation is 0% or 100% is probably wrong. If I flip a coin 10 times and get 10 heads, you can tell me I made my own luck in doing so but it's just another sports cliche, IMO. Some portion of the outcome is dependant on skill and some on luck. Anyone who watches baseball has to realize luck is a HUGE factor.