THE BOOK--Playing The Percentages In Baseball

It’s his BABIP though.  0.221.  And that is not sustainable.  It’s not sustainable for Pedro, it’s not sustainable for Mariano Rivera.  I don’t want to hear about exceptions.

Rivera is at .264 career.  Hoffman at .266.  Percival at .232.  Papelbon .262.  Nathan .254.  Soria .253.  Those are all relievers.

Pedro was at .282.  Moyer from 1994-2010 is at .278.

We know Strasburg throws very hard and has a good curveball.  I don’t know what that means for our BABIP expectation for him.  I agree it seems very unreasonable to expect better than the .250-.260 of the best relievers.  It’s probably unreasonable to expect better than the .280 of the best starters.

The starter/relief translation according to the Rule of 17 is that there should be a 17 point difference.

I was thinking that the limits would be .280-.320 for starters, and 17 points lower for relievers (of the same quality).

I wouldn’t expect Strasburg’s BABIP to be anything special. Even though pitch speed doesn’t have that big of an effect on batted ball speed it isn’t negligible either. His 100mph fastball will be a factor that raises BABIP.

I would expect his game to be more about missing bats than generating weak contact - he’ll be pitching up in the zone with the velo he has.

Yes Matt, but strikeouts are also correlated with lower BABIP IIRC.

All things equal, batted ball speed (and thus BABIP) should go up with pitch speed, but in practice the relationship is not so straightforward.  As Nick says, swinging and missing seems to correlate with making weaker contact.  Here is how that relationship looks for the 15,807 balls in the April 2009 HITf/x data.  All pitch types are lumped together here, but >90 mph should be almost all fastballs, anyway.

(Sorry, Tango.  I don’t know where else to host one-off images except Wordpress.  If I host them on Imageshack or other free image hosts, they’re blocked at my work.  I don’t feel right hosting all my stray images at THT unless I’m using them for an article or answering comments associated with an article there.)

From the same April 2009 data set, here are the results vs pitch speed in terms of safe pct (hits + errors), BABIP, home run rate and ROE rate.

Obviously one could get a much bigger sample from the whole PITCHf/x sample of ~400k batted balls than from the ~16k from April 2009, but this is the data set I happened to have at hand.

With a 65.9% gb rate, I doubt he is pitching up in the zone.

So many grounders may not help his babip, but it helps avoid all types of extra base hits.

It happens that I did have a larger sample of data sitting around, that of batted ball results for all fastballs 2008-2009.  Here is the BABIP vs fastball speed graph.

The size of the error bars reflect the random error from the sample size.  They do not reflect any error from the fact that different fastball speed samples are made up of different pitchers.  For example, I suspect that the 81-mph fastball point is heavily influenced by Jamie Moyer’s data.

It sure looks like he has a lot of sink on his fastball.

And WOW, that fastball is the filthiest I’ve ever seen.

I would think that with that kind of fastball, he would need to learn to throw up in the zone more.  In college and to some extent in the minors, no one is going to square up a 100 mph fastball no matter where it is. In the bigs, they will hit it if it is low and not located well.

Strasburg threw 2 different fastballs last night.  One is the fourseamer at 97-99 with 8 inches of rise and 7 inches of tail.  The other is the “oneseamer” at 95-97 with 5 inches of rise and 8 inches of tail.

I would think he should throw the former up in the zone and the latter down.  BTW his changeup has negative rise and is 91-93 MPH.  Unbelievable.

Yes, very impressive.  Of course a pitcher needs to mix up the location of all of his pitches (although off-speed usually is thrown down), and it depends on the batter and the game situation…

MGL, on the broadcast they said that Strasberg likes to throw the “one seamer”, which is supposed to move like a sinker, because that way he’ll get more groundball outs and won’t run up his pitch count. However, John Smoltz agreed with what you said. He thinks that Strasberg should throw more up in the zone.

Bottom line is that ALL pitchers must mix up the locations of their pitches, as long as one of those locations is not terrible (like deliberately including a hanging curve ball in your repetoire), including high fastballs.

And if you have a very fast fastball, whether it be a 1, 2 or 4-seamer, you need to throw it up in the zone even more, because the harder you throw, the more effective the high fastball is.  It is also true that the more your fastball sinks, the less you want to throw it up in the zone, for any given speed, but you STILL need to throw it up in the zone if it is really fast.  Even a true sinker-baller probably needs to occasionally throw one up in the zone I think (maybe not). 

But Strasburg is definitely not a sinker-baller even though he apparently does get a lot of ground balls (60+%?).  If I am throwing 98-100, you bet that I am going to throw a significant percentage of my fastballs up in the zone.

How often you throw up in the zone also depends on your control.  Pitcher without good control are often afraid to throw up in the zone, for fear that they will throw it too low and it will end up in the hitter’s happy zone, and they are correct in being fearful.  Same thing with throwing inside.  The less control you have, the less you want to throw inside to batters.

Strasburg also apparently has great control, so the more he wants to throw up and inside.

Of course, if a really successful pitcher (or hitter) is not comfortable with doing something that you think is going to make him even more successful, at some point I guess you just let him do his thing.

Strasburg’s BABIP so far in three MLB starts:
0/3 on pop-ups
2/8 on fly balls
5/6 on line drives (plus two LD home runs)
1/15 on ground balls
0/1 on bunts

8/33 = .242

Not that it means much.  I was just counting it up for my own curiosity and thought I would share.