I like Natson's ball security on punts, and his returns have been solid for the most part, though he does do down with any contact at all. But this week's problem with only dressing 2 RB's may need to to remedied. As far as I know Natson only does PR. Not sure if he covers punts. Cooper can KR, PR, cover punts and kicks and line up as a slot receiver. If he's worked on his ball security you'd have to go with him.
otherwise they'd only dress 1 of Kelly or Davis to fill brown's spot.
On a side not, I did see Longacre dressed yesterday. Does he play special teams too? When i suggested last week that they dress O.O instead of Longacre several posters told me that Longacere no longer dresses and OO would take a spot from an LB who plays special teams.