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SIERA Looks at the Upcoming SP Free Agent Market

What does the, arguably, best predictor of future pitching performance think of the upcoming free agent class?

Duane Burleson

The Royals have never been big time players in the free agent market. The biggest contract they've ever doled out was $55M and that went to Royals legend Mike Sweeney then Gil Meche matched that money later with his jersey number. In a bizarre case, Meche would later walk away from $12M of that guaranteed money and retire in 2011 citing that he wanted to "earn" his money and his shoulder injury is just too much to come back from. That was nice.

The Royals will see a hole in their rotation appear as they'll likely lose one of the best pitchers they've had in the past 15 years become a free agent in James Shields. We'll get into future predictions of his skill level a bit later, but Shields has been very good for years and will be paid like a very good pitcher for years. Whether that's wrong or right is a different question as I'd rather pay a player for what he's going to do rather than what he has done, but Shields is probably going to double or triple his net worth come December.

SIERA is a beautiful statistic. It stands for Skill Interactive Earned Run Average and once you grasp the concept of SIERA the name will make sense.

Since the dawn of sabermetrics, sabermetricians have been looking for a more accurate way to evaluate a pitcher than using Earned Run Average. Fielding Independent Pitching has picked up steam recently and I feel like I've seen people embrace and use it more, which is great, but FIP isn't the end for me. It's easier to explain and grasp mentally than SIERA perhaps, but SIERA is slightly a better evaluation and for the purposes of this article specifically it is a slightly better predictor than FIP and xFIP.

I promise you SIERA isn't so hard to grasp if you have the basic concept of FIP down. We'll start off with the similarities. Both think that home runs and BABIP are luck and things that pitchers can't control so both are DIPS metrics essentially, but FIP thinks completely atheistic about luck while SIERA is more agnostic. SIERA doesn't fully believe a pitcher can control his luck, but he does have influences on that luck (hence the Skill Interactive part of SIERA).

Basically what SIERA does is allow for errors bars or explanations for a pitchers results and tries to make an apples-to-apples comparison of pitchers. SIERA knows that batted balls and plate appearance results do account for something.

For example, a pitcher who doesn't walk a lot of batters isn't hurt as bad with a walk as a pitcher who does walk a lot of batters. A pitcher with a very good ground ball rate isn't hurt as much by a walk because he can potentially convert those walks to double plays. A pitcher with high fly ball rates aren't as vulnerable to HR/FB. Pitchers with high strikeout rates generate weak contact which leads to more outs so it thinks strikeouts are more important the FIP. It also realizes that relievers have lower BABIP and HR/FB rates.

All those concepts make sense and SIERA tries to account for them unlike FIP excludes batted ball data except home runs.

Since SIERA has been shown to be the best ERA estimator, and has even bested most projection systems, it should be an applicable metric to judge future talent given even sample size.

For this exercise we'll look at the upcoming free agents, both players without a 2015 contract and those with options (regardless of their chances of being picked up or not). For SIERA we'll look at one-year and three-year data. Also we'll include xFIP in the results.

Name Age xFIP '12-'14 SIERA '12-'14 SIERA '14 Notes
Max Scherzer 30 3.19 2.98 2.95
Hisashi Iwakuma 34 3.30 3.38 2.81 $7MM club option with a $1MM buyout
Brett Anderson 27 3.38 3.42 4.66 $12MM club option with a $1.5MM buyout
A.J. Burnett 36 3.36 3.46 4.11
Johnny Cueto 29 3.40 3.47 3.05 $10MM club option with an $800K buyout
James Shields 33 3.51 3.54 3.59
Joe Blanton 34 3.58 3.66 N/A
Jon Lester 31 3.67 3.75 3.05
Dan Haren 34 3.80 3.76 3.8 $10MM player option if 180 innings reached in 2014
Hiroki Kuroda 40 3.67 3.77 3.71
Francisco Liriano 31 3.60 3.81 3.7
Brandon McCarthy 31 3.65 3.82 3.05
Colby Lewis 35 4.09 3.83 4.14
Yovani Gallardo 29 3.65 3.84 3.77 $13MM club option with a $600K buyout
Josh Johnson 31 3.68 3.84 N/A $4MM club option
Justin Masterson 30 3.81 3.85 4.06
Jason Hammel 32 3.83 3.85 3.27
Carlos Villanueva 31 4.04 3.86 3.94
Jake Peavy 34 4.12 3.92 4.42
Chris Capuano 36 3.89 3.94 3.9
Ervin Santana 32 3.87 3.95 3.5
Josh Beckett 35 3.95 3.95 3.54
Gavin Floyd 32 4.03 3.98 3.56
Chad Billingsley 30 3.90 3.99 N/A $14MM club option with a $3MM buyout
Ryan Dempster 38 3.99 4.02 N/A
Jerome Williams 33 4.06 4.04 3.71
Paul Maholm 33 3.99 4.09 4.74
Wei-Yin Chen 29 4.15 4.11 3.87 $4.75MM club option with a $372K buyout
Roberto Hernandez 34 4.09 4.11 4.72
Brandon Morrow 30 4.17 4.13 4.43 $10MM club option with a $1MM buyout
Ryan Vogelsong 37 4.18 4.18 3.85
J.A. Happ 32 4.29 4.19 4.34 $6.7MM club option
Wandy Rodriguez 36 4.1 4.19 4.31
Felipe Paulino 31 4.27 4.28 5.23 $4MM club option with a $250K buyout
Kyle Kendrick 30 4.26 4.32 4.47
Edinson Volquez 30 4.17 4.34 4.36
Jorge de la Rosa 34 4.22 4.41 4.4
Bruce Chen 38 4.67 4.45 3.71 $5.5MM mutual option with a $1MM buyout
Aaron Harang 37 4.54 4.47 4.21
Joe Saunders 34 4.33 4.5 5.23
Kevin Correia 34 4.4 4.61 4.86

So no real surprise here. Scherzer is the best pitching free agent this coming November and figures to rake in $100M+.

Brett Anderson could be a very interesting option for a team. He's riddled with injury history, but the xFIP and SIERA figures make him look very good. That's a very particular point as well as he's played in two extreme parks (Colorado barely and Oakland). That is...when he's not injured and he just came off the 60-day DL. His 6th DL trip in basically four years.

Let us pray that Bruce Chen's mutual option isn't exercised on the Royals side this upcoming off season. Age and ERA estimators aren't too kind on him.