Win Share totals disagree with you. Over the past four years, the best reliever year (2004 Brad Lidge - 17.2 pitching win shares) comes in as the 38th best pitching year over those past four years, the equivalent of 2007 Zambrano/Lilly. A good example of a pitcher that was both an effective starter and reliever is John Smoltz. In 2004, he was the fourth most effective reliever in baseball (Lidge, Gagne, Benitez). He finished the year with 12.1 Pitching Win Shares. The next three years, he was an effective starter, with Win Share totals of 21.1, 19.4, and 17.5. That's because win shares are awarded to pitchers based on total runs prevented, exactly the sort of system that underestimates a high-leverage reliever. You might as well just use VORP. What are your specific problems with SNLVAR and WRXL? Why are they wrong when they show the best relievers and starters to be closely packed? Win probability is an incredibly important concept to bullpen usage. If we ignore it, then we shouldn't have any bullpen roles at all. Just pull a name out of a hat every time the pen is needed. And it's the exact opposite of arbitrary. Arbitrary would be if the numbers were made up. They aren't.