IRVING, Texas -- The Dallas Cowboys moved up in the NFL draft and selected the best cornerback available in Morris Claiborne with the sixth overall pick Thursday night.

The Cowboys traded the 14th pick and the 45th overall (second round) picks to the St. Louis Rams for the sixth pick.

It was the 59th draft day trade since 1989, the first year that Jerry Jones became owner/general manager of the Cowboys.

Claiborne, 5-11, 188 pounds, was a two-year starter out of LSU who many scouts describe as a smooth athlete with good footwork and balance.

In Claiborne's final season at LSU, he was named SEC Defensive Player of the Year and won the Jim Thorpe Award as the nation's best defensive back. Claiborne finished the season with six interceptions and six pass breakups. He also returned one pick for a touchdown. He also returned kickoffs, averaging 25.1 yards per return. He decided to skip his senior season and leave LSU for the draft.

Adding Claiborne brings some depth to a secondary that was beaten up in 2011.

In free agency, the Cowboys signed Brandon Carr to a five-year contract to go along with Mike Jenkins and Orlando Scandrick. Jenkins is in the final year of his contract and seeking a long-term deal. But with Claiborne on the roster, it will be interesting to see how Jenkins reacts to the move.

Last season, Jenkins finished with a just one interception but was tied with Terence Newman with 10 pass breakups. Jenkins played through knee and shoulder injuries.

The Cowboys were projected to get Alabama safety Mark Barron, but they bypassed him to get the cornerback. Barron went to Tampa Bay with the seventh overall pick.