Board Thread:Questions and Answers/@comment-24386552-20140528161527/@comment-5278765-20141202014129

Heather wasn't ever a series regular. Just recurring. And I'm pretty sure that her leaving because her pilot got picked up is the reason why Shane, Stephanie, and Leah became series regulars. I believe that if she hadn't left, Jo would have been made series regulars and the other three would have stayed recurring, with maybe an additional one being promoted at the end of season ten. But they wanted to have the contracts locked in so that they wouldn't leave.