Watching the Toronto/NY game, and the announcer is talking about Chad Green.
His pitched ball has 2,500 RPMs. So, they have a stat for revolutions per minute!
To the batter it is a ‘fuz’ ball. As they cannot see the rotation.
Apparently the higher the RPMs the more games in the win column.
But, you folks knew that.
I was amazed. Nothing is sacred.
I didn’t see that, but yeah, it’s interesting. Chad Green’s fastball isn’t 100 MPH, nor does have great movement, and yet it’s bloody effective. Hitters call it a rising fastball. It doesn’t, but maybe that is the illusion of a high spin rate.
They have had it in cricket for a couple of years now. It’s fairly important, because a spin bowler will put sidespin on the ball, and when it bounces, the sidespin will cause it to deviate (significantly, in some cases). So the amount of sidespin is significant.
Presumably, in baseball the spin has some impact on the movement of the ball in the air. At first glance - more revs = more movement, I guess.
The idea of ball rotation being important goes back to the days of Cy Young.
The pitch doesn’t bounce in baseball - if it does it’s a wild pitch. A baseball pitch with a tight spin is effective because hitters get confused predicting the aerodynamics of the ball, which in turn leads to an incorrect split-second assessment about where the ball will be when it crosses the zone in which they’re supposed to swing at the ball.
Interestingly, the first time I heard a baseball announcer talk about RPMs was last year when Charlie Morton was pitching game 7 for the Astros. Morton had been a prospect for some time in the eyes of various scouts but his results until last season had been somewhat inconsistent and mediocre. One of the main reasons the Astros took a chance on Morton was because of his RPMS. One of the reasons the Astros went from last to first in just 5 years was because of their cutting-edge analytics.
Hmmm, I didn’t know that even hitters saw this illusion. I assumed it was because of the angle of the camera, looking downward at a slight angle in order to see both pitcher and hitter. You learn something new every day.
Oh, absolutely. A baseball is not a perfect sphere–it has raised stitches on it, which affects its trajectory through the air when spin is imparted on it. If you’ve ever played tennis, you know this effect very well with how top spin, back spin, and sideward spin affects the movement of the ball through the air. This spin is what causes “curveballs” and “sliders” and “cutters” to be possible. (And lack of spin also causes aerodynamic instability in a pitch known as a “knuckleball.”)
It may not be a true “riser,” but if he imparts more backspin on it than is usual in the MLB, the ball will not drop as much as a conventional fastball, giving the illusion of it rising to players who are expecting a fastball they are most accustomed to.
The best hitters do have eyesight and reflexes that good. Another factor is that the “break” (also an illusion) on a fastball will be different if the pitcher holds it across the seams instead of parallel to them. A “four-seam” fastball has a greater difference in drag from its forward-moving side to its backward-moving side, and will move more vertically - but a hitter can see more red on the ball, and can adjust his swing in just those few tenths of a second. A higher spin rate can obscure the difference visually as well as creating more vertical variation from a perfect parabola.
Pitch rotation has always been important, but actually measuring the RPMs seems fairly new. I’d love to know what Pedro’s or Doc Gooden’s fastball RPMs were. Pedro credited his fastball effectiveness to his long fingers being able to stay in contact with the ball longer than other guys, creating faster rotation.
It absolutely is an illusion - it is not possible for a human being to throw a baseball with an upward break - but it’s certainly one the hitter sees. A very hard fastball up in the zone can appear to rise.
The extent to which a hitter can actually see a ball’s spin and react accordingly is probably being a little exaggerated. Sliders and screwballs can have a noticeable red dot effect, and that’s the easiest one to see, but in general a batter is only going to be able to effectively react if he looks for a particular pitch and is correct in his guess.
As to RPMS as an analytic - I mean, it’s working, right?
When I was a kid, being a Blue Jays fan, I got to watch Dave Stieb pitch. Stieb had an absolutely disgusting slider. It looked like it hit an invisible object twenty feet from the plate and deflected off it. Really good hitters would literally miss it by a foot. It was easily the best slider in baseball, and made him a great pitcher and perennial All-Star. No one had a slider like it. When he was on you wondered how he didn’t throw a no hitter every second game.
Today, honest to God, there must be fifty guys who throws sliders like Dave Stieb’s. Everyone has nasty, nasty stuff now. They’re doing something right in selecting and teaching pitchers. I don’t know how hitters do it.
Not really. I watched the closer for the Mariners on Sunday. 2 or 3 pitches about 100 mph Then a slider or 2 into the dirt in front of the plate. All 3 batters for the Indians all swung and missed at the pitch in the dirt. One of those pitches hit about 5 feet in front of the plate and bounced in. Strike 3, he’s was out.
Heh, yeah that happens sometimes. I’ll remark to my wife that it looks like they’re golfing when a batter swings at a pitch on the ground. 
Suffice to say that in baseball, any pitch that touches the ground is one that the batter shouldn’t even be trying to swing at. Some do, sometimes, but it’s a mistake, and a risible one.
I also wonder how much pro batters base their decisions on what they see the pitcher doing before the release, as opposed to the ball’s flight. It’s more subtle, but it also gives you more time to work with.
I haven’t seen a Superball in years, but anyone who played with one knows just how much spin can affect bounce.
Gotta love the completely restrained sportscasters there. 
This is for something that apparently became known as the “ball of the century” and the announcers are acting like it’s just another routine play. “And he’s done it” with only the slightest hint of an exclamation point there, if any. ETA: Maybe there is a slight hint of excitement, and I can see the argument for keeping commentary cool and subdued but, man, is that something I’m not used to!
Right. But pitchers are always trying to fool batters, and some are rather good at it. If a batter resolves never to swing at a pitch that might possibly end up in the dirt, he’ll likely be called out on strikes a lot.
I think the answer is that they certainly try to. But a pitcher whose pitches can reliably be predicted before they are thrown will typically be looking for a new line of work.
I don’t mean completely prior to the throw-- I mean during the throwing motion itself. At some point, your throwing motion needs to be different, for different pitches.
