Danny Duffy’s Live Arm


Last night’s start was much, much better than the start against Houston for Danny Duffy.  In that last start Duffy had a “dead arm” according to Ned Yost, but that seemed to subside against the Cardinals and to great result.  Let’s look at the two starts and see how different they were.

First off, the velocity charts show the basic story.  I grabbed these and a lot of my info from Baseball Savant PITCHf/x Search, which is awesome if you haven’s seen it.

The top one was the dead arm game and you can see the velocity drop off significantly a little over halfway through the game.  There is a little decline in the chart from last night, which is typical for Duffy, but not nearly has big or sudden of a dip and almost got back to 95 on the last pitch.  That lead to much better results.  It is even more promising than that though.  let’s look at his control.

Last night, Danny Duffy threw 85 pitches split 55 strikes and 30 balls, but the game before he threw one more pitch with 47 strikes and 39 balls.  That is a lot more misses and he missed up.  Last night 40, almost half, of the pitches were down in the zone or down out of the zone.  The game before only 29 pitches were down, so two-thirds of his pitches were up.  That is not going to work in the big leagues.

He also changed his pitch mix throwing 8 sliders and 9 change-ups against the Cards and only threw the fastball 64.7% of the time.  Against Houston he didn’t throw any sliders and only 1 change-up, so 80.2% fastballs show that dead arm must come with a side effect where there is no feel for the off-speed pitches.  We saw his strike out rate come back up last night too after three very low strike out games in a row including the good start against Baltimore where he made it seven innings but only struck out 2 batters.

Since returning as a starter, Danny Duffy has 4 good starts and 2 bad.  Hopefully the dead arm is gone and was the root cause of the 2 rough starts, and last night shows him turning things back around.  The control still has some inconsistency as I have discussed before, but he may be one of the most important pieces on this team for 2014 and beyond and last night made me a little more optimistic that for this year he can be a useful part of the rotation in the short-term, which Aaron Brooks proved is very important to this team right now.