Where does cornerback Cox figure in 49ers' plan?

After listing the 49ers' draft "wants" this morning, there were some questions why I chose not to mention one of the team's free-agent pickups.--No mention of Perrish Cox in CB paragraph? Wouldn't he be 4 starter at worse? @hudd07
--Why no mention of CB Perrish Cox in recent articles on defensive analysis and draft wants? @pmensoni
--what happen to Cox isn't he a CB? @CJMackiPerrish Cox was a fifth-round draft pick of the Denver Broncos in 2010. He struggled as a rookie on the field, and nearly destroyed his career off the field, too.The Broncos released him prior to his second NFL season. Cox did not play at all in 2011.The 49ers signed Cox to a two-year contract earlier this month with minimum salaries and no guaranteed money.In other words, the 49ers are giving Cox a chance, but they are not counting on him to be a contributor for the team in 2012.Hey, he might end up realizing his potential and winning a roster spot. But the 49ers are certainly not counting on him to the point that his presence would prevent the team from using a draft pick on somebody at his position.Carlos Rogers and Tarell Brown are the projected starters at cornerback. Chris Culliver looks to be the No. 3 corner. And Tramaine Brock is the clear front-runner, right now, for the job as the No. 4 corner.The onus is on Cox to move up the depth chart. But there are no expectations at this point -- and, really, no reason to factor him into the equation until he proves on the field that he belongs.