Barnes was hurt during the second quarter when he landed awkwardly after battling Jarrett Jack for a rebound. Barnes spun in the air while attempting to control the ball with one arm, eventually coming down hard on his right leg.
Barnes will have an MRI on Saturday to determine the extent of his injury. Jackson said he was "concerned" about Barnes' health.
"I'm going to have an MRI, and then we'll set up a timetable," Barnes said while walking out of Staples Center after the game. "Any time you can walk, it's a good sign ... so just stay hopeful."
Barnes had two points in 10 minutes during the first half, but checked out with 5:22 left in the second quarter of the Lakers' 101-97 win.
Barnes is averaging 7.5 points and 4.9 rebounds in his first season with the Lakers, providing valuable minutes as backup to low-scoring starter Ron Artest.
Backup point guard Steve Blake also injured his left ankle during the fourth quarter, but Jackson didn't believe the injury was serious. Blake also walked out of Staples Center without aid.