While I like the “nobody is safe from bad play” perspective, he wasn’t playing that bad this year. Compared to everyone else, maybe. But he was serviceable and good for when Parsons/LVE or someone needed a break. Or if someone is injured. This decision has to have something else behind it. You don’t get rid of depth like that. Still gotta pay him anyway so why not keep him on the roster?
*edit: he also appeared to be a leader on the defense. He would recognize plays and formations and would call it to the defense. I saw it in some of their huddles. Regardless of how it showed on field, he could recognize the plays and was a leader. Weird thing to do…