An undersized cornerback better suited to nickel and dime packages, Arenas moved into the Chiefs' starting lineup part of last season when they decided to cut starter Stanford Routt.
Arenas, a 2010 second-round pick out of Alabama, finished the 2012 season with a career-high 60 tackles to go with a pair of forced fumbles. The 25-year-old has career totals of 136 tackles and two interceptions in 47 games.
The Chiefs have aggressively remolded their defensive backfield this offseason, luring free agents Dunta Robinson and Sean Smith to compete for the cornerback job opposite Brandon Flowers. They also picked Georgia defensive back Sanders Commings in the fifth round of last weekend's draft.
It's possible that Commings could shift from cornerback to safety.
The Chiefs also drafted a fullback in the sixth round in Braden Wilson, who played nearby at Kansas State. But that evidently didn't deter new general manager John Dorsey and coach Andy Reid from acquiring Sherman from the Cardinals.
"A personnel guy's job is never done, but right now I feel pretty good about going into camp," Dorsey said recently. "For the most part, I feel like the way we are going to camp, we are 95 percent there. This is kind of the way we are going to go to camp."
Sherman is considered a strong special-teams player and served as a captain for the Cardinals in 2012. He did not record a carry last season and has just 14 total offensive touches in two seasons.
First-year Cardinals coach Bruce Arians brought in a new offensive system that rarely uses the fullback spot.
Arians' offense uses tight ends in blocking roles similar to a fullback.
The Cardinals have been seeking depth at cornerback, particularly after losing Richard Marshall and Greg Toler the past couple years. New general manager Steve Keim alleviated some of those problems when he signed Antoine Cason and Jerraud Powers in free agency.
Cason is expected to start opposite Pro Bowl cornerback Patrick Peterson, leaving Arenas to compete with Powers and Jamell Fleming for playing time. The Cardinals also drafted Tyrann Mathieu in the third round, and he can play both weak-side safety and slot cornerback.
Arenas is entering the final year of a four-year deal worth nearly $4 million, and can become an unrestricted free agent after the season. Sherman has two years left on his contract.
Information from The Associated Press was used in this report.