53 is also today's focus in uniform history.
This year, No. 53 belongs to A.Q. Shipley, who will likely be the team's starting center. He was signed this offseason to a two-year contract and is battling Ted Larsen for the starting center job. Shipley has been running with the first team all offseason.
Who else of not has worn it?
Linebacker Clark Haggans did from 2008-2011. One of many former Steelers to pass through Arizona in recent years, Haggans signed with the Cards as a free agent after eight years in Pittsburgh. He added some pass rushing punch, but not a ton of sacks. He started 43 games in 2009-2011 and had as many as five sacks in a season. He was a solis, but not special player.
Back in the first few years of the Cards being in AZ, 53 was worn by linebacker Garth Jax. He was with the team from 1989-1995, although he was really only a starter for 1990 and 1991. He had 70 tackles and three sacks in 1990.
Back in the 60s and 70s, linebacker Jamie Rivers wore it from 1968-1973 and then Steve Neils from 1974-1980.
Who was the best to wear the number? Vote in the poll.
Who was your favorite? Tell us in the comments. The full list of 53s is here.