"I honestly don't know what the future holds for me," the 30-year-old Charles said after being placed on injured reserve Nov. 1 with a meniscus tear in his right knee.
The surgery was performed by Dr. James Andrews, who also cleaned out Charles' left knee. Both procedures were minor.
"(The left knee) wasn't as bad, but there was some stuff in there," Charles said. "It made sense to do it so I could just heal up and go out there feeling the same way in both knees, just completely ready."
Charles is owed $7 million in salary and bonuses next season and will "almost certainly" be asked to take a pay cut, NFL.com reports.
The four-time Pro Bowler played in only three games in 2016 after never properly healing from an ACL tear he sustained in 2015. Charles rushed for 40 yards and one touchdown on 12 carries.
Charles is a nine-year veteran who has totaled 7,260 rushing yards and 43 touchdowns in 103 career games.