ARAM should allow me to pick characters from the available champion bar.

So ARAM can assign me a champion I have never played but when a character I HAVE played ends up in the available champions bar at the top, I can't pick them even if I have played them. I understand the purpose of ARAM is to play random champions, but I should at least be able to take champions the rest of my team doesn't want, despite if I own them or not.