The key word is "pencil". It's erasable.
You "pencil" him in but have contingency plans in place.
1) Peralta
2) Civale
3) Myers
4) Woodruff (written in pencil)
5-7) Rea/Hall/Ashby
Primary Depth:
8) Misiorowski
9) C-Rod
In case of emergency:
10) Gasser (if ready)
11) Henderson (have to add him after the 2025 season anyway)
12) Patrick
13) Shane Smith (have to add him after 2025 as well)
14) Hunt
15) Wichrowski
Also, the Brewers have until four days after the World Series ends to extend Montas and tear up the option year if they feel like Woody isn't progressing. I would not be surprised at all if they do that. I think Montas knows that he isn't getting $20M (from the Brewers or anyone), but might be open to $20M guaranteed over a two-year extension and he really enjoyed being on the team.
Depending on what they think of Henderson, Smith, Hunt, and Wichrowski, they have some young pitching talent to package to pick up an established starter if they need one (but I think they try to extend Montas first).