Pitcher Volatility Part I | Part II

Hitter Volatility Part I | Part II | Part III | Part IV | Part V | Part VI | Part VII | Volatility Calculator

We've just hit September, but already baseball pundits are fiercely debating who should win the 2011 Cy Young award. As the run environment has further declined this year we are left with numerous pitchers whose traditional and advanced statistics look fantastic. This makes the job of choosing a Cy Young winner in both leagues more difficult. Although, I guess that depends on who you ask.

Some think the awards have already been decided, with Roy Halladay in the NL and Justin Verlander in the AL leading the field. Halladay anchors the best rotation in baseball and has been arguably better than last year, while Verlander has seemed unhittable each time he takes the mound.

Both have truly been special, but it isn't as open and shut a case as many think. 

For example, Doc Halladay has been great, but he doesn't look that different from Clayton Kershaw of the Dodgers. Per plate appearance, Halladay walks fewer batters and Kershaw strikes out more batters. Both have very similar ERA estimator scores (i.e. FIP, xFIP, SIERA, tERA).

I thought it might be interesting to introduce the Volatility metric I discussed last week into the debate and see what it might say about the Cy Young discussion.

As you might recall, Volatility for starters is all about how consistent their performances are with their seasonal Fielding Independent Pitching average. So, a starting pitcher with a FIP of 3.00 and a Volatility score of 1.40 will provide their team with a FIP between 1.60 and 4.40 in roughly 68% of their starts during the year. The metric says nothing about streakiness, just consistency on average.

Below is a chart showing the Volatility of the top 20 starters in baseball this year sorted by their FIP. The vertical bar in the middle represents the pitchers' seasonal FIP, while the length of the bars represent the pitcher's FIP range in 68% of their starts.

click to enlarge