Of course he's a potential casualty, as the Jets did bring in Richardson and CJ. Didn't read this anywhere today, but I was just looking. Jets would save a net $860K by cutting him (if Richardson would end up as the replacement, which is as likely as any at this point).
Regardless of how much cap space we have available, $1.431M is kind of a lot for a 3rd string RB who doesn't return kicks or punts. On the flip-side, I don't know how much Smith (or Vick) would be dead meat if Richardson needed to be in there and was kept in to block on a pass play. He's not a rookie or anything, so he should understand these assignments, but I'd be lying if I said I knew his reputation in this regard.
Keep in mind, it's $1.431M gross savings, as his cap number savings gets replaced by another player, not by a zero. Cutting Powell saves $1.431M, but Richardson makes $580K. Presumably the Jets aren't keeping both. Even if Powell is deemed slightly better for this year, is he nearly $900K better than Richardson for 1 season as the 3rd string back?