Averdrian was rumored to be a new champion of the League of Legends. It was thought that he was reworked into Heimerdinger, however, Coronach (Associate Game Designer) stated: "To fuel more speculation, Heimerdinger is not Averdrian and Nidalee is not the Spider Queen." [1]
His head artwork was used as the head artwork for Malzahar on the test realm before his release.
On the 2010 Harrowing map, a coffin containing him (along with the Plant King and The Voodoo Shaman) can be seen. This could be interpreted as the "nail-in-the-coffin" confirming his cancellation.
"Nocturne", the Lead Effects Artist, had Averdrian as his avatar in the forums and was trying to make Averdrian a champion. (In his words (second post) "I'm trying SO hard to make Averdrian a reality. If they close the door on him I will change my avatar."). In July 2011, he finally changed his avatar to the skin Ravager Nocturne, meaning that Averdrian is finally cancelled.