Bucannon fits exactly what the Cardinals wanted to do with the safety position -- he gives them length, speed and a hitter.
He will compete with Tony Jefferson for the starting spot at strong safety.
The selection ends the suspense for Cardinals fans, many of whom were worried that the team would take Johnny Manziel with the 20th pick.
That will conclude the Cards' Thursday night work. They will have three picks on Friday. They have a second round pick and two third rounders --the 52nd, 84th and 91st picks overall.