Johnson's season ended in December when he tore his Achilles tendon in a game against the Oakland Raiders.
"If I'm not 100 percent, there will be some kind of setback," Johnson said Monday as the Chiefs began their organized offseason workout program. "The main objective is to come into camp and get my work done and start training my eyes again.
"I'll be well enough. It'll probably be 7½ months by the time camp comes around so I'll be able to do everything."
Having Johnson, who turns 35 in November, healthy and in their lineup when the season begins has been a goal for the Chiefs. Johnson, a four-time Pro Bowl selection, has been a solid and at times spectacular player for Kansas City for years against both the run and the pass.
The Chiefs have no obvious candidate to replace Johnson as an every-down producer at inside linebacker.