My take: The Cowboys closed the defensive needs by taking Frazier. In the second round they took a linebacker (Jaylon Smith). In the third they took a defensive tackle (Maliek Collins). In the fourth they took a defensive end (Charles Tapper). To start the sixth round, they took a cornerback (Anthony Brown).
Frazier started 13 games in 2015 and finished with a team-high 108 tackles. He had 4.5 tackles for loss and one interception. He finished his career with five interceptions, including three in 2013.
He is more of a downhill safety than a center field safety and has been compared to Church. His immediately contribution could come on special teams. His college coach was John Bonamego, who was a long-time NFL special teams assistant coach.