Percy Harvin has not yet been cleared to practise with the Seattle Seahawks since sustaining a concussion.
The wide receiver was knocked out of last week's divisional round playoff game against the New Orleans Saints after taking just three receptions.
Head coach Pete Carroll confirmed that the 25-year-old is still going through the league's concussion protocol, and that the team is unsure whether he will be able to play against the San Francisco 49ers on Sunday.
Harvin missed the majority of the regular season with a hip injury, featuring in just one game.
