My point is you don't depend on Painter or Abel, if they emerge, great, but you should be conservative with young pitchers.
We're talking the fifth starter, anyone who can put up a 4.50 ERA/FIP is a find for that spot - and Falter did so last season.
Probably need to find 40 or so starts, given the inevitable couple weeks off for Wheeler or Nola.
First half of the season, with rainouts, etc. probably can get by with 5 SPs, but by July or August will need a 6th and BP guys you can rotate between Philly and LV for bullpen games.
Last season
Gibson 31 starts, 167 IP 5.05/4.28
Falter 16 starts, 84 IP, 3.86/4.65
Eflin 13 starts, 75 IP 4.04/3.56
Syndergaard 9 starts, 54 IP 4.12/3.66
Sanchez/bullpen 6 starts
Walker should replace 30 of these starts, hopefully, a notch above Gibson.