MLB stats: Which ones are relevant to handicapping?

[DSzymborski]

(05-08-2012 12:36 PM)JSpauny Wrote:  

(05-08-2012 12:23 PM)ChiefZilla Wrote:  Are there any exceptions to the rule in regards to pitchers?

i.e. Do groundball pitchers generally have lower BABIPs?

I'm not entirely sure it works that way with pitchers. If you look at the leaderboard in BABIP last year, Hellickson, Weaver and Tomlin were all under .255 for BABIP with a GB% less than 40. Defense is huge for pitchers BABIP. I think it's one of the biggest determinants. Does that shot to the hole become an out or a hit? Same with the dribbler to 3rd. I'd factor in defense before GB%. It's why you'll notice that the Rays had some of the lowest BABIPs in the MLB last year, it's because their D was top notch.

The mean's the biggest determinant.

Essentially, if you know nothing about a pitcher other than his BABIP, the expected break-even point (the point at which his actual BABIP passes mean BABIP as the better predictor of future BABIP) is between 3000 and 3500 batters faced (the limited ability to exceed BABIP doesn't generally seem to age significantly).

Assuming Tom Glavine could theoretically come back and pitch at even a passable level tomorrow, if all you knew was his career BABIP, your best guess at future BABIP, without knowing anything additional, would be in the neighborhood of 85% actual BABIP, 15% mean BABIP.

With Josh Tomlin, that would almost flip, 75% mean BABIP, 25% actual BABIP.

With team defense, that gets better, but not dramatically. BABIP above team still leaves you with a break-even point somewhere in the 2000-2500 batters faced range.