I was wondering about this too, so emailed ticket office last night. Got a reply this morning. Fair play to them, quick response and on a Sunday too.
“Thank you for your email. Season tickets will be posted over the next
few weeks or so. We will start printing them shortly and as soon as we
do, they will be immediately posted out to you, in time for the first
home fixture vs. Doncaster Rovers on Tuesday 20th August 2013.
Thank you for your patience at this time.”