Joe Walker
While Walker has been a good special teams contributor in his three NFL seasons, he played a ton of snaps in 11 starts on defense for the Cardinals last season. He won’t make his way into a starting role in San Francisco, but it wouldn’t be a surprise to see him climb over Nzeocha and Al-Shaair in the hierarchy of reserves should one of the three starters suffer an injury. He sits near the bottom for now though.