I actually do not think he is the best CB in this draft. But you are right, his injuries are a concern.
In any case, all this does is raises the value of Jaycee Horn and Greg Newsome, two corners I think the team really likes. If they were already out of reach, notwithstanding a trade up, they are likely going to go even higher.
My sense is, if the Saints go up 7-8 spots, it will be for a CB. If they go up 12 spots, a QB. If they stay put, they could go in several different directions, including RB.