Comparing C.J. Wilson And Edwin Jackson

This winter, we're pretty much looking at two free agent pitchers that could be expected to make a major impact in the near future. If Japanese ace Yu Darvish gets posted, we can call it three, but at the moment we're just looking at two. I suppose now is a good time to re-introduce you guys to C.J. Wilson and Edwin Jackson. Because once they're gone, seeking high-end pitching on this year's free agent market is going to be about as fun as going to a McDonalds with $50. You might be able to afford the filet mignon, but instead you're stuck with 50 McChicken's.

Yeah, there's Mark Buehrle, but we can basically assume that he's staying in Chicago or going home to St. Louis. There's CC Sabathia, but the Yankees can't possibly let him leave, right? There's the Cardinals duo of Chris Carpenter and Adam Wainwright, but the Cardinals aren't going to decline both of their options. Then there are the constantly injured types- Erik Bedard, Brandon Webb, Rich Harden, Chris Young, etc.- and a whole bunch of "meh" guys.

If you're looking to hand out a multi-year contract to a pitcher, it's basically either Wilson, Jackson, a Japanese pitcher or something along the lines of Jason Marquis.

So, understandably, most people expect Wilson and Jackson to make a whole lot of money soon. Tim Dierkes at MLBTR even went as far as wondering whether Wilson could land a $100 million deal as a free agent. But one comment from Tim stood out to me, when he mentioned that Wilson is "easily above" Jackson in terms of what he can command from teams on the open market.

I'm just wondering exactly how much this is the case. Certainly, there are some clear things in favor of Wilson: he's a lefty and he has less mileage on his arm because of the time he spent in a relief role. He's also three years older than Jackson, who's likely to make 30 starts for the fifth consecutive time in 2011. And while Wilson has outperformed Jackson this year, I thought that I'd take a look at exactly how much better Wilson has pitched.

Given that Wilson has started for only two years, that's pretty much the limit on where we can gather information to compare the two pitchers, but we're still talking about roughly 60-plus starts apiece from each pitcher, so we're not just looking at a few games of performance. Before delving into what the numbers mean, here's an overlay of their 2010-2011 numbers side-by-side:

Okay, so we can pretty clearly see some differences. In terms of the actual run prevention on the field, Wilson is clearly ahead of Jackson. His ERA is nearly one run lower than Jackson's, which bears through with particular strength in his rWAR figure. While fWAR depends heavily on FIP, rWAR is based off an adjusted ERA figure, and obviously in terms of ERA you'd have to admit that Wilson is the clear favorite.

So just from looking at those two WAR marks, you'd presumably assume that Wilson is by far the better pitcher, as Dierkes suggests. But it's pretty clear that things aren't that simple when you look at some more complex metrics. In SIERA and xFIP, more complex statistics that generally have stronger predictive power than metrics like ERA or FIP, there's practically no discernible difference between their performance. Wilson and Jackson have practically identical SIERA figures over the past two years, and in xFIP you actually see Jackson having the advantage.

Realistically, most of this stuff kind of points towards one thing: Wilson is better than Jackson. You really can't doubt it by looking at these numbers. He's clearly been better from a superficial perspective, and while the peripheral statistics indicate that things are much closer than they seem, they certainly don't definitively say that Jackson has pitched better.

But on the other hand, I do think that they indicate that Dierkes may have been overstating his case. Yeah, Wilson is a slightly better free agent candidate than Jackson. He's been slightly better over the past two years, lending to some more certainty in terms of what you're going to get over the short-term. There's a good deal of perceived value in that. But is it really worth around $50 million or so? Because right now, that kind of seems to be what Dierkes is suggesting. Generally, most people have pegged Jackson to get something around four years and $50 million to $60 million in salary. Dierkes is suggesting that Wilson could literally double that figure.

All I know is that Jackson is younger, has a longer track record of starting, has a cleaner bill of health and hasn't pitched that much worse over the past two years. I get that Wilson is going to be more appealing to win-now teams because you can feel pretty good about him being better than Jackson in 2012. I'm just not convinced that he'll be so much better than Jackson that it's worth a significantly larger commitment.