What does it mean to be stable as a pitcher? I heard it in a forum once that a pitcher should be stable and flexible.

Can I hear it in a sentence please? 8)

I think he means like, steady, not collapsing or swaying all over the place, in control over your own body.

Physically or mentally?

In the physical sense, I would imagine it means the pitcher has good balance with no inappropriate posture changes during his delivery.

In the mental sense, I would guess it means that he remains in control and doesn’t let things rattle him.

Stable that might have come from me but Idk.

Stable means to not have break down in mechanics and to stay steady and not collasping in the transfer from the post leg to the plant leg till the throw.