He won't rule out the possibility of adding a game to the league slate.
Mike Slive did an interview with Mike Herndon of AL.com about a wide variety of topics about the league. I encourage you to read the whole thing.
One answer did stick out noticeably though:
Q: Do you see the SEC going to nine conference football games at some point?
A: "We vetted that out in Destin. We spent a lot of time on it, and there was an overwhelming majority (against it). The only thing I would say about that is in '14-'15, when the new playoff comes and the selection committee comes, we have to at least be sensitive and alert to make sure that our model, our formula, works for us in the way in which we want it to work. You can never be married to one thing if facts dictate that something else should be done."
Ah ha. So that's why the 2013 schedule is another one-off thing rather than the beginning of a new rotation. The conference is leaving open the option of switching to a nine-game conference schedule in 2014.
A couple things come up here.
First, Slive here is talking about changing to a nine-game schedule for the purpose of enhancing the top teams' strength of schedule. That's an unnecessary solution to the problem. Nothing is preventing teams from going out and scheduling another big non-conference game instead of lining up a bunch of cupcakes. Unless, of course, Slive doesn't think he can convince schools to do it on their own for the sake of improving the overall conference's odds of high postseason paydays.
I'm not completely convinced that schools will be more concerned with strength of schedule than they are now, though. After all strength of schedule was the key factor for Auburn getting left out of the BCS title game in 2004, and precisely no one adjusted their scheduling strategies as a result of it. The SEC, of all leagues, has the least to worry about (at least in the short term) given its unwavering reputation of being the toughest of all conferences. Plus, look at how the Big Ten and Pac-12 killed off their scheduling agreement that would have boosted schedule strength for both of them. It's not a slam dunk that schools will be beefing up their schedules when the playoff comes.
Another possibility, not mentioned by Slive here, is that a nine-game conference schedule could be done for TV purposes. He's in the midst of negotiations with ESPN over not just the new, post-expansion contract but also for starting up a real SEC Network. Adding a ninth league game has the potential to increase the annual amount of money from ESPN as well as introduce more inventory for the conference's channel.
Whatever the case, it's a real possibility that the SEC could go to a nine-game conference schedule in 2014. I'd put the odds well under 50%, but it's out there nonetheless.