"I don't know what I'm going to do really," he said. "It's a day-by-day thing."
The injury causes the swelling of a ligament on the bottom of Johnson's foot and has been bothering him since preseason camp.
"I think it finally caught up with me," he said. "It just isn't getting any better."
Senior Danny Verdun Wheeler worked as the starting middle linebacker Monday, elevating Brandon Miller to the starting spot on the strong side.
Wide receiver Mario Raley (elbow) and defensive lineman Ray Gant (foot) returned to practice in full-contact jerseys. Offensive tackle Michael Turner (ankle) returned but wore a green, non-contact jersey.
Senior quarterback Joe Tereshinski returned to the practice field Monday, which was the first day he hasn't had to wearing a protective boot since suffering a high ankle sprain against South Carolina on Sept. 9.
"I'm just trying to go through the motions a little bit," he said. "It was pretty weak today."
Tereshinski threw a few passes, took drops and ran straight ahead Monday and hopes he'll be ready to return to the lineup Oct. 7 against Tennessee.
"You can never tell, but so far I'm a little bit ahead of schedule," he said.