For what I understand, you are using the prey on Sphinx and want to know if it's possible to roll again and get Sphinx?
If this is the case, I can tell it's possible, I had Draken Warmaster on my prey, got loot prey and didn't have any prey card left, so I rolled again and got Draken Warmaster. You need to be lucky to get the same creature you want, but it's possible.
PS: If i didn't understand correctly please let me know