I agree Ray is one of the better options. He's probably better than Cabrera and Boyd right now, but not better than Shota, at least for now. If Steele doesn't look good, I think the Cubs will try Ben Brown as a SP later in the season and the playoffs, if Ben keeps pitching well. Right now, Ben is looking better than Cabrera and Boyd. Then, use Assad and Steele for long relief.
That said, somebody might get hurt before the TDL, so it's very hard to predict. Like Rcal10 said, way too early, but it's fun to talk about.