What the heck, I'm a Smallville fan and would like to see Michael Rosenbaum return for one last hurrah - so I'll go with it.
Apparently, this is similar to Wiki in that anyone with a computer can edit this. However, I think there is some sort of eventual confirmation. By who? I have no idea.
Screen Rant took it upon themselves to try and get a confirmation, but everyone was mum on the subject.
Rosenbaum has stated in the past that he hasn't spoken with anyone on Smallville, but the show's creators have been pretty vocal about wanting his return.
Rosenbaum appeared in the premiere to Breaking In where he was a big hit with the producers, and is being brought back for more episodes.
We'll see if there is any merit to this story - hopefully soon!