San Francisco 49ers left tackle Joe Staley missed his second straight practice Thursday due to a knee injury.

That's an ominous sign for the 49ers, who have scored only 28 points during their three-game losing streak and saw struggling quarterback Colin Kaepernick sacked six times in last week's 17-3 setback against Green Bay.

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Staley had started 68 consecutive games, the fourth-longest active streak for offensive tackles. If the Pro Bowler is unable to play, the 49ers will likely slide Alex Boone from left guard into Staley's spot for Sunday night's matchup at the New York Giants.

Tight end Vernon Davis, who missed last week's game with a knee injury, and wide receiver Quinton Patton (concussion) were among five players limited in Thursday's practice.

Linebacker Ahmad Brooks has already been ruled out of the game following the death of his sister.

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