Because HR/FB rates are extremely volatile? In what must have been the last few minutes, fangraphs actually put up an article detailing the effectiveness of FIP, xFIP, SIERA, and the various projection systems at predicting future performance. Click here I'll be honest, after reading that I'm considering making the jump to SIERA as my go-to. Just for giggles, here's the aggregate 2010-2011 SIERA for some players relevant to the discussion (I only did two years because Travis Wood only has two years of data): Mat Latos: 3.33 Hiroki Kuroda: 3.60 Roy Oswalt: 3.64 Ubaldo Jimenez: 3.71 Ryan Dempster: 3.76 Matt Garza: 3.79 CJ Wilson: 3.80 Edwin Jackson: 3.92Gio Gonzalez: 3.98 Trevor Cahill: 4.08 Travis Wood: 4.22 Chris Volstad: 4.23 Rick Porcello: 4.25 Randy Wells: 4.31 Carlos Zambrano: 4.39 Paul Maholm: 4.40 Mark Buehrle: 4.56 Joe Saunders: 4.70 Interesting. I still think Jackson is really underrated on this board. Maybe, but Jackson is unarguably a volatile player, and his asking price (thus far) is pretty ridiculous. He's just not likely to be worth the risk, unless the price comes way down. He is intriguing, though. His asking price is absurd, no doubt. I just don't believe, at this point, he's going to come close to achieving that price. As for volatility, yes, but even his "down" years would be helpful. WARs the last four years: 2.1, 4.3, 1.7, 3.1 (the 1.7 is dragged down because he was awful in Arizona; perhaps park effects that the Cubs wouldn't have to worry about? Not sure.). He also pitched at least 183 innings each of those four years. That's nothing to scoff at.