changeup

Yes, Justin. You heard correctly.
A well known 'pitching talk show host'
preaches throwing the circle change almost this way. However I don't recall any 'twisting' of the arm but only 'inverting' his wrist such that
the 'circle' is directed at the plate
at his release point.

And yes, there is controversy
around his 'House Rules'. Yes, this 'instructor' pitched in the big
and was one of those 'crafty' LH coming
out of the bullpen. I recall House
was very active in the biomechanics of
pitching, and 'hung out' with Noly
when in Texas, Bobby Valentine when
in Japan, and more recently, the big
Unit, prior to his back problems.

I think one of the keys to 'inverting'
the wrist is the the range of motion
the player has, which is frequently
guesstimated at the size of the players
hands.

The other variations of the grip
to the change up is as you mentioned,
- the 3 finger. If you experiment
with the thumb and the pinky on your
3 finger release point, you will
have several variations of the other
change up grips e.g. Palm Ball, Paze,
and Fosch.

Dick Bosman Texas Pitching Coach,
likes to put pressure on the sides
of the ball when throwing his change.
I gave Dick, Seaver's pitching book
in hard back cover when Bosman first came up.
Prior to Bosman leaving Balt to Texas
with Oates, I gave him Seavers paper back of a later revision after he complained hard back cover was 'borrowed' (and never returned).

Like all good tools, it may be best
to schedule time within you weeks
to teach yourself the change e.g.
during long toss, and grade yourself
on the mound by throwing your change
for strikes. Like most pitches,
a proper grip, and release point,
couple with good throwing mechanics
work ethics and conditioning will become 'effective and safe' for you.
(Just remember at times, to throw it
and duck ! )