The Kansas City Chiefs have reached an agreement on a three-year contract with free agent cornerback Sean Smith, a source told ESPN's Adam Schefter. Smith was the Dolphins' top cornerback last season, grabbing two interceptions, deflecting 12 passes and forcing three fumbles last season.

The 25-year-old Smith has five interceptions and 40 passes defensed in 63 career games. Kansas City also added former Falcons cornerback Dunta Robinson to a three-year contract on Wednesday.

The 30-year-old Robinson signed with Atlanta in 2010 and became a steady figure in the Falcons secondary, known especially for his bruising hits. He had four interceptions over the past three seasons.

Smith and Robinson join a secondary that already includes pro bowl safety Eric Berry and Javier Arenas. The Chiefs secondary managed to rank 12th in the NFL for pass defense, despite losing cornerback Brandon Carr to free agency and posting a league worst 2-14 overall record.