How many bullpen guys do they have with no options who are expected to make the team as of now? To start rotating in some of the exciting young non-current 40 man guys, it seems like they will need to have a few of that first group either hurt, 'hurt', or gone, but that is tricky since they need all the depth they can get too. Presumably Fields is out of options (I don't actually know) and that is a strike against from this perspective.
Wright’s thingy eases it a bit, but I’d say Hembree and Johnson are locks and Workman and Thornburg are iffy. Johnson’s not appreciably better than either of them, but his five years of team control makes him uncuttable while he’s a decent-enough 6th starter. There are just too many interesting mL pitchers to leave buried in the pen all year. In order of preference, I think Brewer, Putnam, Mejia, Smith, and Ellington could all be playable if healthy.
I also expect that there’ll be a similar bullpen crunch happening leaguewide, which means there could be another wave of perfectly useful pitchers (like Fields) flushed from major league rosters in the next couple months. Teams were able to sign a bunch of decent pitchers to minor league contracts (guys like Norris, Vincent, Clippard, Carson Smith), which will have a ripple effect on rosters. I don’t think teams will see much incentive to tend contracts to their so-so arb-eligible guys next year (Workman types making $1.5-3 million), or keeping guys on the back ends of multi-year contracts (like Tommy Hunter, Juan Nicasio, or Brandon Kintzler). The playable relievers signing mL contracts will be able to do those jobs more cheaply and often with greater team control, and the teams still have to keep lanes open for their minor league pipeline before losing players to Rule 5.
The Cubs have a similar dilemma (and to some extent, so do the Phillies and Yankees). Their bullpen is Strop, Edwards, Cishek, Montgomery, Brach, Kintzler, Duensing and Chatwood, with Morrow and Cedeno on the DL. None of those guys can be sent to the minors except Edwards. When Morrow and Cedeno come back, at least two of those guys will have to be DFA’d, traded, or ‘hurt’, and that’s before they even dip into their own mL pickups or prospects.