I think we need to have another guy who can be a legitimate force inside and this is a possibility that the coaches have decided might work. I don't think it's an issue of not expecting Payne back this year at all. If I had to guess I'd say that they don't want to even think about putting Payne out there too soon and so having a guy like Eaton to start early and spell Payne until he's back in form and feeling confident would be a good thing.
Assuming he's healthy enough to go of course. I think it's caution and nothing more. They're going to be careful with Payne for as long as they can. Losing him last year probably was the biggest single factor in the defenses fall from grace. I hope Eaton has another season or two in him. He could be a great guy off the bench to spell Seth.
A wise man once said "...well at this point it's all been hashed out and you either see it or don't. Hoping for a win next week" - HTown2ATX