I'd be OK with him in the third. We need to address FS at some point since Kazee is on a one-year deal and we don't know how well he'll recover. However, because Kazee has been a pretty decent free safety and I feel we have bigger question marks at CB and DT, I'd like to address those spots first if the value is right. Something like Surtain, Nixon, Johnson, Shelvin would thrill me. I also like Barmore, McNeill and Togiai along the DL, so get me two of those five plus an early corner and a free safety mixed in during the first three rounds and I think we've addressed our biggest areas of need. I can see improving our linebacker depth as well, but I'd rather pick up a couple in the fourth- through sixth-rounds to compete as depth/possible future starters unless there's a value there in the first three rounds that's impossible to ignore.
Of course, there are a few safeties I like better than Johnson, but who knows which ones will make it to the third round.