Present bullpen:
Guaranteed FA contracts: Harvey, Phil Maton, Webb, Millner (LH), Thielbar (LH) (5)
Palancia (6)
Rea, Assad (

Options: Hodge, Brown, Wicks, Little
Non-roster guy with some upside: Snider.
I think Hoyer may be done for guaranteed-contract FA relievers? If you sign more, you're just going to have to cut one (or more), in the event none are disabled by season start.
With Hodge, Brown, Wicks, and Little all scheduled for Iowa, I feel like bullpen is already reasonably deep.
I know the FA's are old or injury-prone or both. So, yeah, I get they aren't all going to both make it out of camp and make it effectively into August. But seems to me adding more guaranteed guys is pointless, and really Webb is the only guy under $3.75. Doubt Hoyer will see enough from any of the ≥$3.75 guys to cut them in camp.
Point being, I think remaining bullpen additions will either be non-roster guys; 40-man waiver pickups who can be released easily; or major-league-contract FA's who can get released in camp without full contract obligation.