Because what you're describing is animation based, at a basic level you can make use of 'on animation finished', so 'on Idle animation finished' set animation to hop. 'on hop animation finished' set animation to idle, to flick between them.
The problem here is when you say hop to the left it sounds like movement and with that logic he won't move so it's up to you how much he moves. What does hop once mean in context of your platformer ? He moves a little bit and plays hop ?
If he moves only when the hop anim plays one time then you could still make use of animation events, so 'is hop animation playing' then simulate control on the frog.