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Washington Nationals: Marquis Pitch Speed Backs Up DL Move

April 22, 2010

Jason Marquis

On Wednesday April 21st, the Washington Nationals placed starting pitcher Jason Marquis on the 15 day DL. Marquis has been rocked this year (20.52 ERA in 3 starts), and the move was not a surprise. Skeptics and conspiracy theorists immediately deemed the move a “fake” or worse yet, accused the Nats of “trying to protect a sucky pitcher”. I decided to compare Marquis’ Pitch F/X numbers from 2009 to this year to see if there was a pattern that might confirm the injury.

Jason Marquis has been a successful Major League pitcher by throwing a heavy fastball/sinker that causes batters to hit the top portion of the ball, inducing ground ball outs.

Results of Injury

If a ground ball pitcher suffers an elbow injury, one of two things can happen to cause him lose his effectiveness:

  • He can lose velocity on the fastball, allowing hitters more time to adjust to the sinking motion of the pitch
  • He can lose some of the sinking motion itself, which also allows hitters to hit more of the ball

Pitch F/X Data

Pitch F/X has a couple of fields that allow us to confirm or disprove this theory. In order to check Marquis velocity, I pulled two fields from the database.

  • Start Speed – The speed of the pitch as measured out of the pitcher’s hand. This is the number most often used on scoreboards and broadcasts.
  • End Speed – The speed of the ball as it crosses the plate.

Here are the results, grouped by month starting in April 2009. The Blue Line is the average start speed for Marquis’ fastball/sinker. The green line is the average end speed.

It’s obvious looking at this chart that Marquis has lost more than 2.5 MPH off his fastball/sinker from 2009.

To be thorough, I also pulled the motion data from Pitch F/X. In his last 3 starts, Marquis’ sinker broke 1/2 – 1 inch more towards a right handed batter than it did in 2009. That’s obviously not much of a difference.

The real story is velocity. It’s surprising that no one wrote this story in spring training. Everyone focused on Scott Olsen’s slower pitch velocity. Marquis probably had the same issues.

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