I'm just wondering why you'd want to do it? :dunno:
Most of the threads on here that contain "Ratchet Rake" and "Piranha Tooth Bar" are of the "which one should I buy" variety. I don't know of too many people that buy both although for back dragging I can see where you might want the Ratchet Rake.
I don't know if it will work or not, so I'll say "Maybe". It will have to depend on the spacing of the Ratchet Rake mounts and if they line up with the teeth of the Piranha. If all of the mounts will fit in a "V", then you might be alright.
BUT... If it were me, I'd just spend the two minutes to take off the Piranha to mount the Ratchet Rake. It's just two bolts, so with my impact wrench and a box-end, there's not much to taking it off.