. . . at least through tomorrow. After that, all bets are off.
Fernando definitely threw a true screwball. I recall James and Neyer saying the screwball was replaced by the circle change which has very similar movement and is easier to throw. There was also a general notion that throwing the scroogie, or fadeaway as Christy Mathewson called it, was hard on the arm. Mathewson said he only threw the pitch a handful of times during a game cuz it hurt so much,
There is no actual data that I could find supporting the idea of screwball induced injury. At least any more so than pitching generally. But this impression might have been fostered by the peculiar and apparently permanennt twist of the arms of Sixties era screwballers Luis Arroyo, Bud Daley and the like. Their pitching arms when not in use did not hang straight down but were turned so that the palm of their hands faced to the rear.
In any event, there are more than enough handside break pitches available now without resorting to something that is harder to throw. EG, if you were in 1928 and watched Felix's change you would be absolutely certain it was a screwball. I would bet, too, that there will be a huge increase in moving two-seamers in the MLB in the next few years after everybody got to watch Kluder in the Series.
Back to Felix for a sec: He semeed to lose control of his two-seamer this year. It always broke a ton but he didn't seem to get calls on it this year. He needs to tame it back to Kluber territory.