A new PITCHf/x chart

For a long time, I've been frustrated by spin movement (Magnus effect) charts because they don't genuinely show how much a pitch actually moves. These charts perfectly demonstrate how the spin of the ball changes its path, but they don't show how velocity adds a vertical element to the pitch's movement.

Take this chart for example. These are the pitches thrown by Texas Rangers LHP Derek Holland during September and October of last season.

Texas Rangers LHP Derek Holland's pitches.

Even though they are much slower pitches, Holland's change ups are located in the exact same place on the graph as his fastballs. If his fastball and change up start with the same trajectory, the change up will always cross the plate lower than the fastball. I wanted to capture this on a chart, so I put gravity back into the equation.

Using Gameday's physics data (initial position, initial velocity, acceleration), I calculated how long each pitch was in the air. Keep in mind, though, that PITCHf/x starts at 50 from the plate and ends just in front. The mapped data covers only about 48 1/2 feet.

With the flight time for each pitch, I calculated the drop caused by [sea-level] gravity. After converting this number from feet to inches, I added the vertical spin movement. Here's how it turned out:

Texas Rangers LHP Derek Holland's pitches on the gravity chart.

Success. The change ups now appear below his fastballs. The chart reflects not only gravity's effect on a pitch, but it also helps separate pitches by velocity, making identification a little bit easier.

This chart does not replace virtualizations by any stretch of the imagination, but I think it does show how different two pitches can be from each other even when spin movement alone can't show it. Taking this a step further could lead to a "hitter's decision" chart that would represent how different the pitches look at a certain time or distance from the plate.

The gravity charts are now available for all pitchers in TexasLeaguers.com's PITCHf/x Database.

[[Update: On April 24, 2010, the Spin Movement w/Gravity charts were updated to reflect gravity's effect from y = 40 to y = 1.417. This change was made based on the information that can be found at Alan Nathan's PITCHf/x site: MLB Extended Gameday Pitch Logs: A Tutorial]]

Texas Rangers Prospects: Derek Holland and Zach Phillips

Derek Holland. The 2006 25th round draft-and-follow signee snuck up on a lot of people last season, including himself. Even Holland can not explain how he gained 5 mph on his fastball during the season.

A lot of pitchers will experience a dip in velocity in their first full years as professionals as the long season wears them down, but Holland got stronger. At the end of the season in the Texas League playoffs, Holland allowed only 1 run over 20.2 innings (0.44 ERA) across 3 starts.

He won't be sneaking up on anyone this year. He'll start the year in the Oklahoma City rotation, but he could be in Arlington sooner rather than later. The development of Holland's breaking ball will likely determine how soon.

The two angles in this video are not the best, but you can surely see some similarities to Tim Lincecum. They share a similar stride and an intense trunk flexion. Each launches himself forward with such force that he flies through the air dragging his back foot like an anchor before landing firmly on the front leg.

Hat tip to Steven Ellis' PitchingClips.com for the image.

At this point, both pitchers have their trunks extended (bent backwards). As the hips turn forward, the trunk flexes and drives the throwing shoulder almost directly over the front hip.

Where they really differ is in their arm actions. Holland picks the ball up early; the ball is at driveline height before his front foot lands. Lincecum picks the ball up fairly late; the ball is still near his hip until right before his front foot lands. Holland picks the ball up with his shoulder. Lincecum picks the ball up with his elbow and has to forcefully externally rotate his arm to position it for the throw.

Holland takes the ball further toward third base than Lincecum takes the ball toward first base. When Holland starts to drive his pitching shoulder, his arm and the ball are accelerated toward first base before they are accelerated toward the plate. This large lateral acceleration results in forearm flyout that is not present in Lincecum's delivery.

Holland releases the ball with a low 3/4 arm angle and has a very clean follow-through with no noticeable recoil.

If you think Holland looks a lot like Lincecum, wait until you see UCLA freshman RHP Trevor Bauer.

Zach Phillips. Another left-handed draft-and-follow pitcher, Phillips struggled in his first full season assignment despite a wonderful short-season debut. In his second attempt at the Midwest League, Phillips stood out as one of the best pitchers. 2008 was another let down year, but if the pattern holds, Phillips could be primed to re-breakout.

Phillips is a pitcher with very typical traditional mechanics. His arm gets up just a little bit late, and he has a late forearm turnover as a result. The inertia from his shoulder drive causes a reverse forearm bounce, but he gets his elbow up to limit forearm flyout.

Even for slow-motion video, Phillips' motion seems very deliberate to me. He might be well served by speeding up his tempo.

All that said, Phillips is very fluid and repeats his mechanics extremely well. He pitched very well in this outing, but for now, it looks like he's headed for the Frisco (AA Texas League) bullpen.