Edinson Volquez' ERA Cannot Last

by R.J. Anderson on May 18, 2008 7:29 PM EDT Comment 7 comments

This is based on nearly 1,000 cases since 1999. Essentially it's baserunners per nine rankings of pitchers with at least 150 innings in that season and the correlation to their ERA. I included pitchers with at least 40 innings thus far this year to get closer to 1,000. What the correlation shows us is that this can tell us to a pretty decent degree what an ERA SHOULD be.

For those a bit unfamiliar with how to plug the numbers in just follow the formula at the top right of the image [.4902*(baserunners9) - 1.7145] and we'll get a "projected ERA". Amongst those whose ERAs have been amongst the most lucky this year: Edinson Volquez (projected ERA 3.85), Fausto Carmona (4.9), Tim Lincecum (3.84), Daisuke Matsuzaka (3.76), and John Lannan (5.14). The unlucky ones include Johnny Cueto (3.58), Dave Bush (4.53), Ted Lilly (3.95), Justin Verlander (4.78), and Jarrod Washburn (4.32).

If you're an owner of Volquez and you need another position, it would be smart to cash in now. He's not going to erupt, but that sparkling ERA is going to go away sooner than later.

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It's a good thing...

that correlation=causality.

by Gray on May 18, 2008 11:16 PM EDT reply actions 0 recs

I’ll assume you meant =/=.

A 91% strand rate obviously won’t last.

"I've seen many, many blue skies turn gray, but the sun will eventually return, and so will I. So will I." - Carlos Pena

by R.J. Anderson on May 19, 2008 2:57 PM EDT up reply actions 0 recs

If I remember correctly

a 60% strand rate won’t last.

still needs more Bonds

by JI on May 19, 2008 7:42 PM EDT up reply actions 0 recs

No, I meant =, because above you write that his ERA will rise since baserunners/9 implies a certain ERA.

I’m more interested in all the factors that you left out. What about K/9 and HR/9 (both fantastic for EV)? What about where those baserunners are? I find it easy to believe that it’s a lot easier to strand a baserunner on first than to strand one on third.

You just seem to imply that the only other possible factor is luck, and while baserunners/9 appears to be fairly highly correlated with ERA, it’s not perfectly correlated by any means, and I suspect there are other major factors besides it and luck.

by Gray on May 19, 2008 7:45 PM EDT up reply actions 0 recs

sarcasm aside...

I agree. Although the correlation is pretty good, it isn’t perfect. I notice some very notable outliers there in that plot and there is no reason to believe that the only reason for the outliers is luck.

The assumption here that a correlation reflects an underlying truth and that outliers are lucky (or unlucky) may or may not be true, but it is testable. What might be more instructive, would be to look at the cases of outliers in the plot in the first half of the season (e.g. 2 SDs away from prediction) and see how they perform in the second half.

by DenverBears on May 20, 2008 4:35 PM EDT up reply actions 0 recs

Well...

Volquez’s QuikERA, which predicts future ERA better than actual ERA, is 3.63. Yes, it’s higher than his actual ERA based off of fewer than two months of starts, but it’s also pretty damn impressive, and given his strikeout totals should still leave him amongst the elite as long as he doesn’t start giving up home runs.

"I don't set the rosters, I just make fun of the guy who does" - Rob Neyer

by Marc Normandin on May 20, 2008 8:16 AM EDT reply actions 0 recs

Several GB pitchers in there

Volquez is getting 54% GB’s at this point with 14% LD’s. Perhaps this is the reason behind the reason for his low ERA? (Both numbers are well off his career numbers, btw.) Batted ball numbers generally stablize quicker and Volquez has faced 227 hitters this year. A little regression, sure, but I see some evidence that he can hold this.

http://mvn.com/mlb-stats

by pizzacutter on May 20, 2008 4:55 PM EDT reply actions 0 recs