A Saints source said the report is inaccurate but did not offer any further details.
Lewis was absent from Tuesday's practice, though it's unclear when the potential injury occurred. He played in Sunday's preseason game against the Houston Texans.
Losing Lewis for a month or more would deal a severe blow to the Saints' defense. He has emerged as their No. 1 cornerback and arguably their defensive MVP over the past two years, routinely matching up against opponents' top receivers.
Plus the Saints' secondary was already dealing with several injuries. Newly signed starter Brandon Browner has been out for the past three weeks with an unspecified leg injury -- though he was back doing individual drills in Tuesday's practice. And safety Jairus Byrd has missed all of training camp while rehabbing from an unspecified knee injury. Coach Sean Payton has said the Saints' goal was to get Byrd back during the preseason, but his timetable remains uncertain.
The Saints also placed rookie cornerback P.J. Williams on injured reserve Tuesday -- though the third-round draft pick had not yet worked his way into the mix for a prominent role on the team before the injury.
The Saints will likely promote Canadian Football League transplant Delvin Breaux into their starting lineup. The 25-year-old rookie has had an impressive offseason after a remarkable comeback from a broken neck suffered in high school.
The Saints will have bigger question marks at their nickel and dime spots, though, with rookie Damian Swann, second-year pro Stanley Jean-Baptiste and veteran Kyle Wilson battling for those jobs after inconsistent offseasons.
The Saints' secondary was arguably their biggest area of concern heading into this offseason, after they finished 31st in the NFL in yards allowed last season and dead last in defensive efficiency, according to ESPN Stats & Information. That certainly hasn't changed in the wake of their summer injuries.