The team began some work Tuesday at University of Phoenix Stadium, with the first of two "QB School" sessions with rookies, quarterbacks and a handful of players returning from injury.

Coach Bruce Arians had previously said Mathieu and Rucker likely weren't going to be ready for the beginning of camp. Bethel had been hopeful he'd be ready. All four can return at any point in camp once they are cleared to play.

The absence of Bethel further throws into flux the cornerback situation. The veteran should be the favorite to win the starting job opposite Patrick Peterson, but he missed all of the offseason with his broken foot and now must wait to get on the field.

The Cardinals recently signed veteran Mike Jenkins to compete for the job and had fellow veteran cornerback Chris Culliver – who himself is coming off an ACL injury – in for a visit this week. The team also drafted Brandon Williams and Harlan Miller at the position.