yes, you're right kumek. A nordgen doesn't reappears in the list.
As a matter of fact, it's more possible to "loose" a nordgen.
In my first levels, I spot some nordgen whose auctions ended after 1-1.30 hour. When I log out and log in again (after 1/2 hour), they weren't on the list anymore. So, after that, when I see a nordgen I 'm interesting for, I "mark" him - not bidding on him but put him in my favorite list. After that, if I log out/in, he is still there.
Also if refresh the list, every 15-30 min, it's possible to see some new nordgen.
But in your case, if no one is bidding on that player, you could buy him for 1 T and test him. If he is an academy player from a team named Immortal and he is slow trainer (which is more possible) you can sell him asap
- but it's not worthy to go on a bidding war for that player.