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Starting Rotation – Command of the Strike Zone

February 16, 2010

With pitchers and catchers on their way to Viera, it’s a good time to look at the candidates for the 2010 starting rotation. John Lannan and Jason Marquis are 1&2. Assuming Santa has moved to DC (he confused us with the North Pole?) and the Nats sign a healthy Chien-Ming Wang, that leaves two spots open to competition. Using the PitchF/X data from MLB, let’s see what we can learn about Nats pitcher’s command of the strike zone in 2009 to help predict 2010.

After a long winter, some of you might need a reminder of the Nats 2009 pitching line.  I’ve included it here, along with Jason Marquis’ numbers.  Chien-Ming Wang pitched a couple of games while injured. By and large, his 2009 numbers are meaningless and have been omitted from the remainder of this discussion.

To show each pitcher’s command of the strike zone, I used the same technique that I used in a recent post called The Book On Zimm. I broke the strike zone into a 5×5 grid.  The center 9 squares (inside the red box) are strikes, and the outer squares are balls. We can use that same technique to graph every pitch thrown by the Nats in 2009.

We’ll start with John Lannan. 50.16% of the pitches John threw in 2009 were in the strike zone.  Here is his breakdown (remember this is from the umpire’s perspective, right handed batters are on the left of the chart).  The left chart shows the pitch locations. The center chart is the opposing hitter’s batting average by zone. The chart on the right is opposing hitters slugging percentage by zone.

This is a very solid performance – a lot of pitches in the zone. The only real trouble spot was outside of the strike zone.  From a right handed batter’s perspective, pitches under the strike zone on the inside part of the plate were hit often and hit hard (.500 AVG, .857 SLG).

Here is the same chart for Jason Marquis. He threw 44.72% pitches in the strike zone.

While Jason didn’t have a high percentage of pitches thrown for strikes, it is easy to see how he kept opposing hitters AVG and SLG down.  Look at the lower right corner (low and away for a right handed batter). 6.62% of all the pitches he threw in 2009 were in that area, yet opposing hitters hit 0.000 for the season!

Now lets look at 2 pitchers who probably won’t be starting for the Nats in 2010 – Garrett Mock and Shairon Martis.Only 38.46% of Mock’s pitches landed in the strike zone. I can understand why he didn’t want to throw strikes – when he did, batters got hits. In five of the 9 areas that comprise the zone, opposing batters hit over .380.  It would take a significant improvement for Mock to start in 2010.

Shairon Martis had a little bit better control. 41.47% of his pitches were in the strike zone.

His problem was that opposing batters teed off when he did throw strikes.  In two of nine grids, opposing batters hit for .500 or better, and slugged for .950 or better.  When he kept the ball low, he was very effective, but it’s too hard to hit the needle in a haystack over an entire season.

Now for the contenders.  Both Scott Olsen and Ross Detwiler had similar strike ratios.  Olsen hit the strike zone 48.27% of the time, Detwiler 48.42% of the time.

Olsen was very consistent, with AVG a little too high in most areas. Pitches right down main street were a problem – 0.923 SLG. There were other areas of concern.  8 of 25 areas had a SLG greater than .667.

Overall, Detwiler’s 2009 numbers are the best of the contenders.  The only outsized numbers he put up were in areas where he didn’t throw a lot of pitches – low and in to lefties and low and in and up and in to righties.

Craig Stammen hit the strike zone 41.16% of the time.

The upside to Stammen is that, even though his strike percentage was relatively low, the opposing batters’ AVG outside the zone was low.  So, he was doing a good job preventing solid contact.  There is certainly something to be said for that if he can keep it up in 2010.

J.D Martin and Collin Balester are the final two pitchers with a chance of starting for the Nats in 2010. They also had similar numbers last year. Martin hit the strike zone 44.69% percent of the time, Balester 44.05% of the time.

In 5 of the 25 grids, opposing batters slugged .800 or better. Someone in the organization is going to have to figure that out before the Nats can let him start in 2010.

Collin Balester had 6 of 25 grids where opposing batters slugged greater than .833.  He also had two areas (comprising 9% of all pitches thrown) where batters hit .600 or above.

My take on the numbers – if Detwiler and Stammen show minor improvement over their 2009 performances, they are in the lead for the last two spots.  Scott Olsen, if healthy, is in the running, with Ballester, Martin, Mock, and Martis bringing up the rear.

What do you think?

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