I wouldn't say Gary Rydstrom has nothing to his name. His resume is just a bit esoteric to turn into a blurb for average movie patrons.
http://www.imdb.com/name/nm0003977/
I admit it does seem like they're dumping this film in the post holiday dead zone. This could have been the last thing in the pipeline other than The Clone Wars before the Disney deal, and it was too far along to pull the plug. Or else they just didn't want to kill George's last "hands on" project?