Introduction: Buster Posey recorded a put-out and an assist on a strike-em out, throw-em out double play in the seventh inning of last night's win over the Reds. The throw elicited all sorts of ohs, ahs, and shameful behavior by Giants fans. Was it that great? or are we just accustomed to a catcher who uses his arm more for reaching for that extra slice of pie, than for throwing out baserunners?
Terminology and standards: "Pop" is the name given to the elapsed time between the pop of the ball into the catcher's glove and the pop of the ball into the second baseman's/shortstop's glove. It comprises the "catch-to-release" interval and the flight interval. Major league catchers' pop should be two seconds or less (Ivan Rodriguez had a pop of 1.8 or less in his prime). A release interval of under 0.7 seconds is considered to be excellent. Throw velocity can be measured with a radar gun, or computed, based on the distance traveled (127 feet, calculated by the Pythagorean Rule) and the flight interval (which is pop minus release interval). The standard for excellence is 70 mph.
Methods, Data and Results: using the MLB game highlight video and an internet stopwatch, I timed Posey's release interval four times at .67-.69 seconds. His pop was 1.9.(1.87-1.90) This gives a flight interval of 1.2 s to traverse 127 ft., which means the ball was moving at roughly 105 fps, which translates to about 72 mph. Error analysis was not attempted.
Obviously, subjectively, his accuracy was fine.
Conclusion: Analysis of Posey's throw (SSS, I know) suggests that, while not in the class of legends like Pudge Rodriguez, Buster is capable of excellent throwing performance.
Or, in the words of Mike Krukow, "you're a catcher, right?"
Addendum: Bengie Molina caught the second game of the Cincinnati series and threw out a runner. Bengie's numbers are as follows: pop 1.93 s, release time 0.69 sec, velocity 69 mph.
In other words, Molina's numbers are almost the same as Posey's, within the margin of error, though his arm may not be quite as strong. I think this confirms my subjective opinion before I made these measurements: Molina is pretty good at throwing to second, and the steals in recent weeks have not been his fault.