Tony Stewart admitted his leg will only be at about 65 per cent come the season opening Daytona 500.
He has been doing extensive physical rehab since being released from hospital following an Aug. 5 Sprint Car wreck that sent the NASCAR champion to hospital.
He underwent surgery on his right leg, and has a titanium rod installed to help recovery.
"This is an injury that's not healed 100% -- there's no bones about it," Stewart said during a media day press conference.
"But it is reality that it could get injured again."
He has been cleared to drive, however, starting on Feb. 14, in time for the Sprint Unlimited practice sessions.