The 31-year-old could add depth and experience to a secondary that has seen three backup safeties injured over the past several weeks.
Ian Rapoport of NFL.com first reported the visit.
That left third-year player Tre Boston, with six career starts, as the starting free safety.
The Panthers had several backups they were high on until injuries. Fifth-year veteran Trenton Robinson was having a solid camp until suffering a shoulder injury that required surgery in last week’s exhibition against the Tennessee Titans.
That left basically Colin Jones as the backup for both safety spots, which are somewhat interchangeable in Carolina’s defense.
He ranked second on the Browns in tackles last season with 81. He also had 1.5 sacks and a forced fumble.
This wouldn’t be the first time the Panthers have turned to an older veteran for help in the secondary. They signed then-31-year-old Harper in 2014 and then-34-year-old cornerback Charles Tillman last season.