Porter hurt his neck last Sunday while making a tackle against Tampa Bay. Robinson is having stomach pain.
Coach Sean Payton hopes one, if not both, will feel well enough to play in Atlanta on Sunday. In the meantime, though, veteran cornerback Leigh Torrence is working as a first-team cornerback along with starter Jabari Greer, while rookie Johnny Patrick is lining up in formations with five defensive backs.
"I'm optimistic about Tracy. We'll see where Patrick's at," Payton said. "The other players got good work in today and that's kind of the way our league is. The next guy's up and he's getting the practice (snaps) and you just have to be able to adjust."
Patrick has been inactive in five of nine regular season games, including the past four. When he has played, it has been on special teams.
Copyright 2011 by The Associated Press