Dougherty had a nice article on roster spots. Basically, 4 TBD- 5th starter, 2 bullpen slots, 1 bench slot
Loser of 5th starter in line for long man in pen. Voth a potential dfa if he's not starting ahead of Ross. Fedde has an option. Other bullpen slot has Baucus, Clay, McGowin, and one other guy on 40 man, plus 3 NRIs- Guerra, McFart, and Avilan. McFart, Avilan, and Clay are LHP. For bench, he lists Garcia and Antuna but then says they are minors destined. Also there Noll. An NRI like Mercer or Adrian Sanchez, Parra, Perez or Yasmani Tomas could grab that spot if they free up a roster slot with a release or a trade