Based on last year I'd have Lopez, Ryan, Woods Richardson, Bradley and Abel in the rotation with Festa, Prielipp and Ober in the bullpen. Matthews becomes the 6th starter with Morris, Rojas and Culpepper as starters 7-9. I think there's still room to bring in another arm to keep Klein, Adams and Raya stashed in AAA to start the season.
We'll see which players show up healthy and performing in a month and it should sort itself out.