There are some internal options. Michael Wacha is the obvious choice, but as we’ve seen, he’s not reliable. His stress reaction could pop up at any time and he’ll be out for a few weeks. I think he’s better suited to the bullpen and a potential “fireman” type in the mold of Andrew Miller from the post-season.
Trevor Rosenthal should be considered. Rosenthal threw 4 good pitches as he made his way through the minors and could still hit 97-98 in the later innings of his starts. After having problems in 2016 and losing the closer role, the team was talking about stretching him out anyway to be the fireman in the ‘pen. Why not see what he could do?
You can also look at some guys in the minors, but I don’t think they are as appealing as Rosenthal. Marco Gonzales is just about ready to go after his Tommy John surgery last season; while he’s still young and has shown promise, his time in the majors hasn’t been great. Mike Mayers was added to the 40-man last season and didn’t look strong in his start; with that out of the way, he could look to build on his limited experience. They could also turn to Luke Weaver; like the other 2, he’s seen limited MLB time but didn’t look ready. He’ll need more time in Triple A before he’s a regular contributor. John Gant is another possibility; the righty pitched with the Braves a few times last season and could be serviceable in spot starts, but I don’t think he’s a long term option.
There are a few non-roster guys too. The best of them is probably Austin Gomber; he’s the most ready of the pitching prospects not on the 40-man, but he could still use a little minor league seasoning.
Unlike past years, the team didn’t bring in any veterans on minor league deals; they could use that depth now and there are guys available.
The one I like the best is Doug Fister; he was one of the more underrated pitchers in the game with Detroit a few years ago. Since then, he’s battled injuries and hasn’t regained his form. He doesn’t throw particularly hard (high 80s), but limited contact and generated groundballs when he was at his peak. He’s be a good reclamation project.
Another solid option is Mat Latos. Latos was the ace of the Padres and Reds a few years ago, but, like Fister, got derailed by injuries. Since he left was traded by the Padres, he’s played in quite a few hitters parks; moving to St. Louis (if he were to make the team), Busch Stadium would be an asset to him.
Other options include Henderson Alvarez, Jorge de la Rosa, Matt Harrison, Edwin Jackson, Colby Lewis, Tim Lincecum, Justin Masterson, Jonathon Niese, Jarrod Parker, Jake Peavy, Alfredo Simon, Jered Weaver, and C.J. Wilson. Of those, Parker and Lewis would be the most appealing. I don’t see a reunion with Jackson or Masterson.
The good news is these external options could all probably be had on a minor league deal; if they don’t pitch well in spring training, you could stash them at Memphis until they hit their stride or the hit an opt out of the contract.
Of everyone listed, I like Rosenthal the best; he’s already with the team, we know what he’s capable of, and Wacha is there to take the role he was penciled into. After that, I’d want Fister and hope he can get back to his 2014 peak form.