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After signing Dahl, it is crucial that the 49ers pick up a free agent cornerback to improve the secondary.
Carlos Rogers and Chris Culliver are both streaky players. Terrell Brown has been consistent, but he cannot be relied on to cover other team's top receivers.
The 49ers have reportedly been interested in Nnamdi Asomugha. Although he has had two bad years in Philadelphia, there is a chance that the former Golden Bear and Oakland Raider could revert to his old self in the familiar stomping grounds of the Bay Area.
Antoine Winfield is another possibility. Despite being 35 years old, he still can play at a high level. He could contribute for a year, giving younger guys time to develop.
Brent Grimes is another option, though he is coming off a season-ending knee injury.
All three players would be an improvement over Carlos Rogers, whose 2011 season is beginning to look like a fluke.
Should the 49ers pick up a serviceable free agent corner, they would probably release Rogers. They could then use at least two of their 14 draft picks to add talent and depth to their secondary.