from Amazon
Sunday, July 06, 2008
Fox and home park radar guns versus Gameday
I was watching the Giants/Dodgers game last night and noticed, as I’m sure lots of people did, that Zito was throwing his fastball 86-88 mph, or something like that, at least according to the Fox broadcast.
I also noticed that Chan Ho Park was throwing in the mid-90’s, which seemed a little high, although I vaguely remember him throwing that fast in his last start as well.
The Giants’ announcers remarked that Zito has been throwing a lot harder in his last few starts.
Anyway, I checked Gameday today, and it had Zito throwing around 85-87, a little less than the Fox numbers I think, but still higher than his average so far this year, at least according to Fangraphs, which has him at 84.3. These are fastball numbers of course.
Park, on the other hand, was clocked by Gameday at 90-93, around 2, maybe 3 mph less than Fox and apparently the Giants home park speed indicator.
What is up with that?
I have a few questions for the people that follow and research this stuff.
I know that lots of the pitch f/x authors have mentioned this before, but at what point is the pitch being measured by pitch f/x (which is the same as Gameday, right)? We know that the pitch speed decreases a lot (3-4 mph?) from the pitcher’s hand to the batter, so where it is being measured is critical in terms of any kind of consistency.
What about the TV speeds? Where do they come from and where are they measuring the pitch (from the pitcher to the batter)?
What about the home park measurements?
What about BIS? Where do they get the pitch speeds from?
Is the Fangraph data from BIS or from pitch f/x? It can’t be pitch f/x can it, since they (Fangraphs) have data from 2005?
Has Zito really increased his velocity over the last X number of starts?