Ahead of the start of free agency, Insider is providing buyer's guides for all 32 teams: biggest need positions from Football Outsiders, top targets from KC Joyner and Matt Williamson and predictions on how everything will play out from our NFL Nation team reporters.
Included below are links to every team's article. This is the entry for the San Francisco 49ers.
Biggest needs
Cornerback: The San Francisco pass defense was quietly excellent last year, ranking fourth in DVOA (defense-adjusted value over average, explained here), and 11th or better against No. 1 wide receivers, No. 2s, and all other wideouts. However, starting corners Perrish Cox and Chris Culliver are both about to hit the open market. At 27 next year, Culliver is the younger of the two and has played well as a nickel and a starter, so he should draw a higher paycheck.