As long as Johnson participates in Thursday and Friday practices, there is no real need to get concerned about this. Rather, this post is more just to make sure you've got this on your radar. For guys like Johnson, it's easy to stick them in your lineup and only make an adjustment when their bye week comes around. You'll want to keep an eye out for Thursday and Friday injury reports.
As long as Johnson practices before the end of the week, he's good to go for this Sunday, which means you'll keep him in your starting lineup. The Texans are facing a struggling Pittsburgh Steelers squad and Johnson could be in line for a particularly strong day. Not that you wouldn't start him if you were worried about a strong secondary.