Judging by ERA, Seattle’s Erik Bedard (2.82) and Los Angeles’s Randy Wolf (3.23) would appear to have had the best seasons of this winter’s crop of free-agent starting pitchers (min. 70 IP). But did they?
Expected Fielding Independent Pitching (xFIP) tells another story. By its lights, Rich Harden (3.70) and the Cardinals’ Joel Pineiro (3.76) were best. Sometimes, the disparity between ERA, which includes a lot of defense and “luck” noise, and xFIP is great. The following chart shows today’s free-agent starters in increasing order of the positive difference between their ERA and xFIP.
With that 2.82 ERA but a 3.92 xFIP, Bedard was the biggest beneficiary of ERA, while John Smoltz was the most “unlucky.” Note that just because a pitcher was “lucky,” it doesn’t mean that he was bad: Todd Wellemeyer, with a positive difference in ERA-xFIP (0.59) and high xFIP (5.30, shown on the blue line), is an apt example.