It's only you who can make that descision i'm afraid. Personally, i would've knocked it on the head.
However, a few months ago, i had a 14" gin rin sanke jump out of my pond. I don't know how long it had been on the patio but my guess would be a fair while.
But i saw a slight movement so i put it in a bowl of pond water and held it there for half hour. By this time, it had shown incredible strength and was almost swimming on it's own.
I added an airstone and after 4 hours, the fish was back in the pond as if nothing had happened.