No matter what formula you use, there will be an outlier.
Hardball Dynasty – Fantasy Baseball Sim Games - Player Profile: Frank Lewis on my Scottsdale team is that guy. He constantly shows up in my top 15 based on formulas. Yet, in 200 BL innings for me, he's gotten destroyed. So, despite the formula, his results say "No, don't use me." He doesn't even pitch well in AAA.