Marcio Jose Sanchez/Associated Press
Rookie CB Kenneth Acker has had a strong showing this preseason.
Retained: Eric Reid (FS), Antoine Bethea (SS), Tramaine Brock (CB), Chris Culliver (CB), Jimmie Ward (DB), Craig Dahl (S), Dontae Johnson (CB), Chris Cook (CB), Darryl Morris (CB), Kenneth Acker (CB), C.J. Spillman (S)
Cut: Bubba Ventrone (S), Perrish Cox (CB), D.J. Campbell (S), LJ McCray (S)
The first five defensive backs on the list of retained players all make sense. These guys will comprise the first-team units in a standard nickel-based defense for the 49ers in 2014 barring anything unforeseen.
Competition certainly heats up thereafter, and the 49ers will have some very tough decisions to make when they formulate a crowded secondary.
Let's first evaluate why veterans Craig Dahl and Chris Cook remain on the roster. Dahl hasn't exactly had the best preseason so far, having shown weakness in coverage on multiple occasions. His performance against San Diego on August 24 was especially forgettable.
But according to Matt Maiocco of CSN Bay Area, Dahl remains ahead of rookie defensive back Jimmie Ward as the team's primary backup safety, per defensive coordinator Vic Fangio. His abilities on special teams also cannot be overlooked.
Cook is another intriguing player. The 6'2", 200-pound cornerback struggled in his first four seasons with the Minnesota Vikings, but the 49ers like his size and strength.
His lack of ball skills—described further by Matt Barrows of The Sacramento Bee—is an obvious concern, but Cook will likely enjoy playing in the press-based defense employed by Fangio and secondary coach Ed Donatell.
Darryl Morris gets a nod based on his speed alone. The 49ers don't want to lose that.
This author lists rookie Kenneth Acker as the final roster addition to San Francisco's defensive backfield. His performance against the Denver Broncos on August 17 was enough to warrant my attention.
San Francisco does not want a repeat of what happened last year with cornerback Marcus Cooper—a talented rookie who the team wanted to place on the practice squad but was snatched up by the Kansas City Chiefs.
Look for the 49ers to try and avoid that mistake again.
This means, of course, that another player out of the secondary will have to go. A few of them, to be precise.
D.J. Campbell has flashed some moments this preseason, but it is hard to see him being retained. The same could be said about rookie UDFA LJ McCray.
McCray was all over the field in San Francisco's final exhibition on Thursday versus Houston. He's vying for a roster spot even if it's distant. Perhaps the 49ers hope to stash him on the practice squad if he clears waivers.
The tougher cuts may include C.J. Spillman, Perrish Cox and Bubba Ventrone. All three of these players have shown their abilities on special teams, and the 49ers don't want to see much of a lapse in this unit.
We'll give Spillman a roster spot for now, given his prowess on special teams as a gunner.
But we essentially know what we'll get out of these three veterans. Their ceiling has been reached, and the fact they remain on the bubble indicates their chances of being retained are weak at best.