The Vikings need plenty of help in the secondary, and one candidate has emerged.

A source said Wednesday the Vikings are expected to take a strong look in free agency at Miami Dolphins cornerback Nolan Carroll when he becomes a free agent Tuesday.

The Vikings ranked last in the NFL in 2013 against the pass. Shoring up the secondary will be one of the top priorities for Zimmer in his first season.

Carroll appeared in all 16 games last season, starting 12, and was third on the team with three interceptions. Carroll, 27, has played all four of his NFL seasons with the Dolphins and made $630,000 last year.

Miami’s linebackers coach the past two seasons, George Edwards, is now Minnesota’s defensive coordinator. When Vikings coach Mike Zimmer was Cincinnati defensive coordinator, Carroll played against the Bengals in each of the past two seasons.

Carroll had a strong game at Cincinnati as a starter in 2012 with four tackles and a pass defended.

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