This post will probably be anything but simple (not using the KISS method). But I think it looks at some of the dangers in looking only at ERA+ or LERA; more specifically, that any LERA value under 100 is absolutely "good" or that any value over 100 is absolutely "bad".
I think we need to look at the context of these values to the league-average ERAs and establish what the true difference between some % above or below this average really means for teams when it comes to winning.
6 of the pitchers from the above free agent list weren't more than 3% better than league average for their careers.
Randy Wolf - 103 ERA+ (3% better than league average)
John Thomson - 103 ERA+
Miguel Batista - 103 ERA+
Steve Trachsel - 101 ERA+ (1% better than league average)
Jeff Suppan - 101 ERA+
Aaron Sele - 101 ERA+
We've been discussing relative value of starting pitchers with above or below league average ERAs. So I'd like to compare starters to starters from this point forward, if you'll grant me the premise. And regular starters, at that. We'll look at all pitchers who had at least 140 IP in the 2006 season.
LERA 140+ IP S-ERA Min Max Med
NL 4.49 49 4.30 2.98 6.02 4.20
AL 4.56 45 4.37 2.77 6.36 4.40
LERA - Overall league average ERA
140+ IP - # of pitchers in each league to throw min. innings
S-ERA - Starter's average ERA with at least 140 IP
Min, Max, and Median ERA for this group of starters
We see that the regular starting pitchers have a collective ERA 0.19 runs less than the overall league averages for both the NL and AL. This inherently make sense, as teams use a majority of their effective pitchers in the starting role when possible. We also see that the median values are close to the average (S-ERA) and that the ERAs are approximately normal in their distribution.
My point with these numbers is this: Is there really that much of a discernible difference between the seasons of a pitcher with league average vs. +/- 3% of league average ERA? Let's look at an example from the American League.
IP BB K W-L ERA %SERA VORP
Pitcher A - 196.0 55 134 13-9 4.27 97.7 33.1
Pitcher B - 181.2 81 160 15-13 4.31 98.6 26.4
Pitcher C - 200.0 70 156 15-10 4.50 103.0 29.2
VORP, created by Keith Woolner of Baseball Prospectus, is a league, park, and position-adjusted measure of a player's worth over a readily-available replacement level player (Major league back-up/AAA call-up). For pitchers specifically, it's a measure of "the number of runs a pitcher surrenders below what a replacement level pitcher would have given up in the same number of innings".
10 points of VORP correspond to roughly one win. So Johan Santana (VORP 79.6), clearly the best pitcher in baseball, is worth almost 8 wins more to his team than a replacement level pitcher would be.
Although Cliff Lee of the Indians was probably the best fit for
the league average S-ERA (Pitcher B), I chose Ted Lilly of Toronto instead to compare favorably with the hitter's parks that Pitcher A and Pitcher C call home. Pitcher A is Jose Contreras and Pitcher C is Vicente Padilla.
VORP does depend on playing time, or innings pitched in this case, and is part of the reason that Padilla had more value than Lilly this past season. But we also see that Contreras and Padilla pitched about the same amount and that the differences in their S-ERAs (~5-6%) only results in a change in VORP of 4 points. These four points add about 0.4 wins to Contreras' team over what Padilla could have provided. Certainly not significant enough to say that one pitcher should be considered a "good" free agent and the other one not.
I know both Padilla and Contreras each have career LERAs under 100, but I wanted to use just a single-season example to show what the spread of these numbers really amounts to.
I echo my sentiments from the previous comment that the 3 pitchers listed in the original article got contracts that were above and beyond what their skill set should have warranted. But we should know that the difference between the career LERAs of these three: Eaton (108%), Marquis (106%), and Meche (105%) and some other starters likes the ones listed above: Trachsel, Supppan, and Sele is really not as much as the percentages may seem.
I know the author of the original post understands this with his skepticism shown in the recent deals for Suppan ($10.5 M/year), Miguel Batista ($8.33 M/year), and Vicente Padilla ($11.25 M/year); three pitchers with just slightly under average career ERAs.
"People ask me what I do in winter when there's no baseball. I'll tell you what I do. I look out the window and wait for spring."