I don't think those cuts would help the 2019 team either, at least not at the beginning of the year. However, there are going to be difficult cuts on this D regardless, and if those cuts come from areas of depth, like the secondary, there doesn't need to be a signing to offset those savings.
With DMac carrying the biggest cap number behind Brady, renegotiating with him seems likely. A $9.5M payout seems steep for one year for him. Harmon has filled-in capably as a deep safety, even if he lacks the man coverage skills, but with the CB depth, there are options. DMac is pretty much family and could be a starter for 2 or 3 more years, so I expect a renegotiation gets done there.
I'd expect to see Roberts and Pennel cut (maybe Ebner goes, too) and extensions worked out with 2 of 3 of DMac, HT & KVN. Still, there always seems to be some veteran cut that surprises us, so I compiled the list to see if anyone stood-out as being that guy. Maybe I'll make an actual prediction after Thursday's game.