Among the Cardinals' post-rookie minicamp moves Monday, the team signed linebacker Airius Moore (left) and wide receiver C.J. Duncan after seeing them on a tryout basis.

Rookie minicamp is always an important moment for first-year NFL players not only because it is their first time on the field as a professional.

It's also an immediate proving ground to reiterate that rosters are always shifting in the league.

The Cardinals made a handful of moves Monday, signing four tryout players: rookie Vanderbilt wide receiver C.J. Duncan,

 rookie North Carolina State linebacker Airius Moore, offensive lineman Greg Pyke and defensive tackle Siupeli Anau – whom the Cardinals just released last week but who was brought back to participate in the minicamp on a tryout basis.

Pyke spent time with the Bills in training camp last year.

To make room on the roster, the Cardinals released cornerback Elijah Battle, linebacker Mike Needham, wide receiver Jonah Trinnaman and offensive lineman Austin Olsen, all of whom were officially signed Thursday as part of the Cardinals' undrafted rookie free agent class.

Duncan, 5-foot-10 and 195 pounds, had 52 catches for 517 yards and five touchdowns as a senior. The 5-11, 230-pound Moore led the Wolfpack with four interceptions last season, to go with 67 tackles.

Anau, a Northern Arizona University product, spent most of last season on the Cardinals' practice squad.

The Cardinals return to the field Tuesday with the first organized team activity work of the offseason in the beginning of Phase Three.