The move was inevitable after coach Jonathan Gannon confirmed on Saturday that BJ Ojulari's knee injury was season-ending, but the Cardinals made it official on Monday when they placed the second-year outside linebacker on Injured Reserve.
The Cardinals now have two open rosters spots for any potential Ojulari/OLB replacement. The question will be whether the Cards choose to add bodies to fill out the roster and lean on those currently on the roster to fill Ojulari's snaps, or if they sign an experienced veteran who could conceivably aid the unproven pass rush.
"You don't have to say much," coach Jonathan Gannon said after news of Ojulari's injury broke. "They are NFL football players. They know it's kind of the known unknown. They feel bad for their teammate. A lot of guys have been through (that injury). He'll lean on those guys.
"But it's a you-know-what part of the business, but we know it happens. They have to pick up their head, the sun's out now, and we've got to go to work."
The Cardinals held a closed walkthrough on Monday. They return to practice on Tuesday.
Veteran Dennis Gardeck was taking first-team snaps in Ojulari's absence during Saturday's practice, and Gardeck was a starter last season when Ojulari was a rookie. Like the defensive line, outside linebacker is a position defensive coordinator Nick Rallis prefers to rotate heavily. Last year's leader in OLB snaps was Zaven Collins, and he didn't quite reach 60 percent at the spot.
The Cardinals did not sign a free agent at the position, but did draft Xavier Thomas in the fifth round.