The page does list him as being 'rumored' for the part but since it's listed in his credits, perhaps there may be some possibility of this possibly being true.
The question is, is Yelchin, or more importantly, is his hair right for the role? He's six years younger that Andrew Garfield but I'm sure they can pull playing the same age. Yelchin has played different types of roles. You've probably seen him as Kyle Reese in Terminator Salvation and Chekov in Star Trek. I just saw him the other day in a 2007 movie with Robert Downey Jr (that I mentioned on the podcast) called Charlie Parker.
I loved James Franco as Harry but Yelchin wouldn't be a bad choice. If he does play Harry, who will play Norman and will we see the Green Goblin (again)?"