No, when you release a Pokemon it is gone for good. All Pokemon you encounter are different and their IVs are randomly generated.
Furthermore, the Pokemon in each area are mostly fixed and their levels are fixed to a small range. In other words, if you released a level 100 Patrat near route 1, you would never see that level 100 in the wild. And the same deal if you released a legendary or your starter, you can never see it in the wild.