Jonathan Gannon had said that the release of veteran linebacker Krys Barnes was about "roster mechanics" and now what those were is clear.

Barnes, who had been cut and signed to the practice squad over the last two days, was officially signed back to the 53-man roster on Thursday when the Cardinals placed rookie cornerback Elijah Jones on Injured Reserve with an heel injury suffered in Denver last weekend.

Jones is eligible to return at some point. The Cardinals could only put two players on IR during final roster cuts that could return, and they used those spots up on defensive lineman Darius Robinson and tackle Christian Jones. To get Elijah Jones on IR but still with a chance to return, they needed to keep him on the roster initially -- hence the back and forth with Barnes.

Elijah Jones, like Christian Jones and Robinson, must miss a minimum of four games before he could return.

With Barnes moving up, it opened another practice squad spot to the two already available. With those three vacancies the Cardinals signed tight end Jordan Murray, late of the Colts, defensive lineman PJ Mustipher, recently with the Eagles, and offensive lineman Luke Tenuta, who had been with the Packers.