The 49ers need cornerbacks. The need is so glaring that general manager John Lynch isn't bothering to play coy in advance of free agency. Last week, as Lynch discussed the 49ers' interest in cornerbacks Vontae Davis, who signed with the Bills, and Marcus Peters, who will be traded to the Rams, he said it didn't take a "savant" to see the team's CB cupboard was a bit bare. Lynch also referenced the roster hole when discussing how last year's release of cornerback Tramaine Brock after a domestic violence arrest came with a cost. "… He was a starting cornerback for us and we didn't take that lightly," Lynch said.