Starters: Ahmed Plummer, Jason Webster, Tony Parrish, Zack Bronson. This is a quality starting secondary, and should be even better than last year. It's a close call, but Parrish looks like an upgrade over the departed Lance Schulters.
Roster locks: Mike Rumph, Ronnie Heard, Chad Cota. Rumph and Heard will play a lot this season. Cota needs to catch up on system before season begins, but his experience at free safety will keep him on roster.
Definitely staying past this cut: Rashad Holman, Jimmy Williams. Both could make team, but only if Niners go heavy on defensive backs, which appears likely since they're trying to catch the Rams.
Where it starts getting tricky: John Keith. The Niners have to figure out what they're going to do with this guy. Now might be the time.
Headed for injured reserve: Kevin Curtis. Too bad, because he was really coming along and looked better - and more athletic - before he got hurt than Cota does now.
On the bubble: Al Blades, Clevan Thomas, Brian Smith, Teddy Gaines. The Niners have to cut players, so probably two and as many as three will come from the defensive backfield in this round. These four are top candidates for the heave-ho.
Blades hasn't show much because of an ankle injury, so he might get the early hook. Thomas, signed Wednesday, must show a lot in a short period of time or else he's gone. Smith has done some nice things and probably deserves to stick to the next round, but he'll ultimately be cut so the Niners might do it now. At this point, Gaines is the weakest of the DBs that started training camp, but he's a draft pick who has some skills, so the Niners might keep him around until the final cut and sign him back to the practice squad to develop him for the future.