When asked a general question about the Ravens' secondary during a conference call with Baltimore reporters, Marshall was effusive in his praise of Webb.
"Oh my gosh, Webb when I was in my last year in Denver, I remember traveling to Blattimore and he really dominated me," Marshall said. "I wasn't prepared. Right before he got hurt, he was probably a top-five cornerback in the league, if not maybe even playing right behind Darrelle Revis, pushing Revis for the best corner.
He was limited to five catches for 30 yards the next year against the Ravens while playing for the Miami Dolphins with Webb frequently matched up against him.
Webb tore his anterior cruciate ligament last year against the Dallas Cowboys, but is coming off his best game of the season with his first interception this year and six pass deflections in a 20-17 overtime win Sunday over the Cincinnati Bengals.
"Now you're starting to see him get back to that form," Marshall said. "He's playing lights out there are some things where I can see he probably wants to work on and not give up, but this guy has the potential to be the best corner in the league.
"We have our work cut out for us. The young guy from Colorado [cornerback Jimmy Smith] is playing really good. He's trying to take away all the deep stuff. It's going to be tough."