I think if this was the NFL 10-15 years ago where there was still a place for the traditional 'in the box' safety he would have had a better shot. He was never particularly great in coverage despite having good speed. To use a Mike Mayock term, he couldn't 'flip his hips' and turn and run with receivers.
In todays game your safeties are asked to cover so much more.
If he could put on a little more weight he could play linebacker or special teams. He's got more than enough speed to rush. Not saying he would be good or not good the way he is now
I don't think he was even given a chance. It appears they already had their eyes on another player, and as soon as he was signed they let him go. It wasn't due to anything on the field.