Best case scenario for the rotation by the end of 2021, barring a free agent signing, I think is:
1. E-Rod (I really hope that he's able to come back)
2. Sale (returns midway through 2021 right?)
3. Perez
4. Eovaldi
5. Houck
If Pivetta can force his way into the group, fine, but I'm not sold on the guy.
I do hope we make at least one significant starting pitching pick up in the offseason, because the worst case scenario is E-Rod is gone, Sale never gets back to what he was, Eovaldi spends 2/3 the season on the IL, the league figures out Houck and he never makes it, etc. Reality will likely be somewhere in between those two extremes.