Big 'Smallville' Spoiler
This was foreshadowed by the surprise ending of last Friday’s episode Beacon, in which Tess Mercer (Cassidy Freeman) discovers to her shock that Alexander (Lucas Grabeel, HIGH SCHOOL MUSICAL) is becoming invunerable.
Producers Brian Peterson and Kelly Souders are quoted as saying:
“Conner’s [sic] journey is manipulated by a master. Luckily, someone knows more about Conner’s life than he does. But he should be wary of strangers bearing gifts.”
So it doesn’t look (at the moment) like the Alexander clone will age into the Michael Rosenbaum Lex. It will be interesting to see how the character will return in the series finale.