Relative Velocities

How many times have you been watching a game or engaged in conversations with fellow fans in which the topic of velocity differential between pitches and its effects comes up? The idea in that tremendous offspeed pitches can enhance a fastball has somewhat grown into the conventional wisdom. It may seem odd at first, but throwing a devastating changeup can make an 89 mph fastball feel like a 93 mph fastball, perhaps even higher.

From a pure logic standpoint it makes sense. Consider this scenario: You are standing on the middle of the road and five cars are driving towards you, one at a time, at say 15 mph, from a great distance. But then the sixth car moves at around 30 mph. You aren’t very likely to know exactly how fast that sixth car is but it is going to seem much faster than its actual speed due to what had previously been experienced.

It was mentioned in the comments section of Dave’s article about Jamie Moyer that perhaps he has been able to strike hitters out or simply continue to get hitters out at his age, with a lack of tangible skills, due to his relative velocity; that is, the difference between the velocity of his fastball and his changeup confuses hitters and deems him a bit more effective than we might give him credit for.

Here are the top ten fastball-changeup dropoffs this year, using the BIS data, and their velocity dropoffs:

Mike Mussina, NYY: 15.8 mph
Vicente Padilla, Tex: 12.3 mph
Zack Greinke, KC: 11.9 mph
Johan Santana, NYM: 11.5 mph
Tim Lincecum, SF: 11.3 mph
Edinson Volquez, Cin: 11.0 mph
Oliver Perez, NYM: 11.0 mph
Javier Vazquez, CHW: 10.9 mph
Barry Zito, SF: 10.6 mph
Tim Hudson, Atl: 10.6 mph

And the bottom five:

Brian Bannister, KC: 4.3 mph
Derek Lowe, LAD: 5.1 mph
Greg Maddux, SD: 5.4 mph
Shaun Marcum, Tor: 5.7 mph
Josh Beckett, Bos: 5.8 mph

Of those in the top ten, the only two that throw below 90 mph, on average, are Mussina and Zito, who clock in around the 84-86 mark. Mussina has been in a relative velocity league of his own this year, throwing an 85.9 mph fastball and a 70.1 mph changeup. Now, pitchers don’t follow a uniform routine of changeup usage: some will throw it much more often than others. Mussina only throws his 6.9% of the time whereas Johan Santana has done so with 26.8% of his pitches.

Looking at pitchers who throw their changeup at least 10% of the time, Johan finds himself atop the relative dropoff leaderboard and new names like Cole Hamels and Brandon Webb join him. The sample of players is likely too small from just one year to find any type of significance or trend within the data, and even then, a regression amongst others would need to be run as a starting point to find what type of effects this dropoff has, which I could perhaps get into in the near-future, but if this relative velocity really matters as much as our logic and commentators suspect, then it should be fairly easy to find a meaningful correlation between dropoff and some form of success.