Corbin, Gray, Gore, Williams, and Kuhl, barring injury, are the initial five.
Camerato's latest opening day 26 has Alex Colome rather than Espino on it, along with Ferrer. Espino is a bit of a surprise. I don't know if that's a team control thing so he can start in the minors, but otherwise I thought he would be a long guy / spot starter / rotation replacement. Erasmo Ramirez I guess is the emergency starter in that case, or perhaps Ward.
I'd say Abbott is a potential 6th guy stretched out in the minors. I think once the roster starts to get a little looser with 60 day ILs, guys like Tetrault will work his way back into consideration.
As for Rutledge, I think another year of managed workload, jump from 97 IP to maybe 130 would be the target. Get him 25-30 starts? If he is on that pace and healthy, then as IanRubbish suggests, he's a rotation add maybe 2d half of the year, replacing Kuhl or an injured guy. Irvin is also in the mix.
I actually liked last year that they let guys like Aaron Sanchez, Cory Abbott, and Josh Rogers get playing time. Didn't go well often, but Cory Abbott looked useful for stretches. I wouldn't hate if he was first man up this season.
I'm just down on the pitching in this system. I'm not hopefully of any rookie pitcher this year really contributing. I have more hope that some random pitcher on waivers may come through and contribute. Surely we can find our own Austin Voth success story.