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." 
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 was finally cancelled.