ComingSoon picked up on casting director Ros Hubbard talking to IFTN about the talented Irish actors working on The Hobbit and slipped Saoirse Ronan's name into the bunch. While this doesn't confirm she is in fact in the film it does mean she could be in talks. The story doesn't name a role but it's assumed it could be that of female elf warrior Itaril. It's likely that more casting announcements will be made in the next couple of weeks.
“[W]orking with Peter Jackson is like working with a family. So they’ll have a great time. Saoirse’s family will go too. Everyone is very close and very loving on those sorts of jobs. It’s not like typical studio movies at all.”