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SANTA CLARA -- Right tackle Anthony Davis, who sat out Sunday’s game due to a concussion he sustained a week earlier, is still experiencing symptoms, 49ers coach Jim Harbaugh said on Monday.
Davis’ availability for the 49ers’ game Thursday night against the Seattle Seahawks appears to be in doubt.
He has to remain symptom-free during four separate phases to pass the NFL’s concussion protocol to return to action.
A player must begin with light aerobic exercise, then move on to strength training, following by football specific activity and, finally, full practice participation and contact without signs or symptoms.
Jonathan Martin made his sixth start of the season on Sunday in place of Davis, who has missed games earlier this season due to hamstring and knee injuries.