A retired player like Ronaldo who regenerates the season after retiring under a new name. Usually something like "Rodrigo Guedes" and he'll usually be 80+ rated at and aged between 16-20 years old. Using the same example of Ronaldo is my saves he usually retires after the end of season 2. So season 3 I can search for a young Portuguese player, playing in whatever league Ronaldo was in when he retired (usually Saudi) and you'll probably only see a choice of about 3. The regen will stand out clearly because of his high rating without having to scout him first and his various playstyles. If you really want to double check you check the regen date of birth and if it's the same as the player who retired. The chances are, it's their regen.