One of the major themes of the Steve Keim era as General Manager is taking veteran players who've been released by other teams, and signing them to short term "prove-it" contracts.
It's not a new practice in the NFL, but it's arguably worked better for the Cardinals than any other team. John Abraham, Karlos Dansby, and Antonio Cromartie are examples of past success stories. And there are several on the current roster hoping to help the Cardinals to the postseason, while helping themselves to big dollars next offseason.
Running back Chris Johnson appears to be the player in this category poised to have the biggest impact in 2015.