Okung, who Carolina acquired from the Los Angeles Chargers this offseason, missed 10 games last year with a pulmonary embolism due to blood clots.
The veteran reportedly seriously considered opting out of the season prior to Thursday's deadline.
In late July, Okung took to Twitter to seemingly air his grievances about the United States' response to the coronavirus crisis.
In March, the Panthers traded five-time Pro Bowl guard Trai Turner for Okung in a rare player-for-player swap.
Greg Little, who struggled in three starts in 2019, would likely be the first replacement option at left tackle if Okung does retire.
Okung could also be forced to return $2.5 million in signing bonus proration if he walks away, Fowler added.