I know Anderson was hurt this preseason, so maybe they are mixing Hawes in for that reason. He is also listed as the first backup for both guard spots and center, so maybe they want to reduce the wear on him.
But a TE like Hawes makes more sense. I kept waiting on Anderson to catch a wide open TD last year, but it never happened. Using a TE will keep the defense more honest than Anderson, and Hawes seems to just as good at blocking.