I've been messing around with MLB Gameday's pFX pitch data. I can't claim I understand it to the degree that some do, but I wanted to investigate the difference between the gopher pitches Street has thrown, and his normal pitches. These are admittedly very small sample sizes, so take it with a grain of salt.
Because the first game was in Japan, complete pFX data is unavailable for the first game. So we'll start with the second game, on April 2, against Boston. Varitek hit a home run off of a change up, at least as classified by the pFX system (which may or may not be accurate with respect to pitch identification). He threw 20 pitches that day...7 were changeups, averaging 84.75 mph at the release point. pFX shows his fastball at only 88.43, however, so there isn't a whole lot of difference. Two of Street's change ups were around 80 mph.
It's possible these pitches were misclassified. If not, his change isn't much of a change.
I graphed the difference between the change up he threw to Varitek on the homer, and the 6 other change ups he threw that game. First, the chart, then some explanation:
The top point on the blue line represents the average release point for the 6 non-HR change ups he threw, and the bottom point on the blue line represents the average location of the change ups as they reached the front of home plate. The top and bottom of the strike zone are represented by the purple lines...and they are averages of the strike zones of the batters Street faced in Boston that day. The top point on the yellow line represents the release point on the change up to Varitek, and the bottom point is approximately the height at which Varitek made contact.What is clear from the graphic is that Street's release point was further left on the home run ball, and instead of a falling motion (induced mostly by gravity), it crossed the plate slightly outside (to Varitek) and right in the middle of the average strike zone. MLB pFX reports this as an 86 mph change up. He had thrown two earlier change ups to Varitek in the at bat, averaging 80 mph...both for balls.
In the game against Cleveland last night, Hafner hit a fastball into the seats. It was the third fastball of the at bat. Street threw eight other fastballs during his appearance. The average speed at release was 89 mph, which is about the speed of the fastball he threw to Hafner.
Here's the chart for that one:
It shows that Street's release point was off to the left on the HR ball in this instance too, and the pitch ended up in Hafner's wheelhouse.One note: the downward slopes of the lines represent only starting and ending points for the pitch. It does not indicate the pitch "broke" in that manner. The lines include the effects of gravity.
