Ward last played for the Tampa Bay Buccaneers in 2017. Before that he played for the Denver Broncos, with whom he won Super Bowl 50, and the Cleveland Browns. He was named to the Pro Bowl in 2013 and 2014.
He has eight career interceptions, 10 forced fumbles, four fumble recoveries, 8.5 sacks and 44 passes defensed.
He'll give the Cardinals depth at safety after injuries have depleted the position. Arizona is already down Jalen Thompson, who was put on injured reserve with an ankle injury on Sept. 17, and is likely to be without both Budda Baker and Chris Banjo this week.
Baker, who signed the largest contract for a safety in the NFL on Aug. 25, had surgery on his thumb this week, but coach Kliff Kingsbury did not put a timetable on his return on Wednesday, and Banjo is out with a hamstring injury. Neither Baker nor Banjo has practiced yet this week.
Arizona is expected to play rookie Isaiah Simmons at safety this week, but Ward gives the team flexibility and an option to add another body to the active roster, if needed.