Polian ranks Brown as the best cornerback in unrestricted free agency. Polian gives Brown the nod over several top-notch free-agent cornerbacks such as Vontae Davis, Dominique Rodgers-Cromartie and Aqib Talib.
If just one NFL team agrees with Polian, the 49ers may be hard pressed to keep Brown. Cornerbacks are often paid at a premium price, so if Brown is coveted, he may be looking at a big contract.
Brown is one of the 49ers' free-agency priorities. CBS Sports reported the team is pushing to get a deal done before free agency starts next Tuesday.
Brown was a starter last year, but lost his job late in the season when he was hurt. However, he did regain it in the playoffs.
Brown would likely be a starter again if he re-signs. If not, the 49ers will get Chris Culliver back from a torn ACL. At the very least, he will be the nickel cornerback. They could also try to replace Brown in free agency with someone like Seattle's Walter Thurmond. In either scenario, the team will likely use an early draft pick at the position.