It's not about which starter has to sit.
Clay will start again if there's an injury or some one needs to skip a start, due to the sucky schedule (I'm thinking Pomeranz).
Otherwise, he's the long guy.
With the exception of E-Rod, this team has been healthy, starting pitcher-wise.
If their luck runs out, you'll see Clay start.
I don't see why they'd bother with a 6 man rotation.