Good thread idea. No, I don't think they'd let him run, but it would be fun to see.
He plays two positions that incur a lot of big-time injuries. Jack would be integral to our offense so quickly, we'd want to keep him as healthy as possible, especially given that we can get a guy to take the RB snaps in the 3rd round.
We don't talk all that much about adding Jack to the roster, but it'd be like having another Sean Lee out there. He's be an impact player immediately, and we'd be finding ways to get him on the field the same way we did with Byron Jones last year. He'd be a good pick for us if the QB isn't there.