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Correction: Grant Balfour's fastball is straight

Yesterday, I commented on an interview with Andrew Friedman, and checked the facts of a few of the assertions he made. One of those assertions was that Grant Balfour still has the characteristics that made him successful. To evaluate that statement, I presented this graph, from Baseball Heat Maps, showing the changes in Balfour's horizontal fastball movement over time.


Unfortunately, I made an error reading this graph that was not only incorrect, but also completely opposite to the truth, and very misleading. Much thanks to community member SagehenMacGyver47 who alertly pointed out the error. I'd like to nip this before it spreads, since I know that the horizontal movement of Grant Balfour's fastball is all anyone is talking about in Tampa Bay right this moment.

Right-handed fastballs have negative horizontal movement in the PITCHf/x system, so by moving from -2 to 0, Balfour's already straight fastball has lost movement and has gotten straighter.

There will be plenty of time to analyze Balfour fully this offseason, but getting the facts straight now is a good start.