Detroit cornerback Chris Houston and safety Louis Delmas are inactive for the second straight game, leaving the Lions short-handed in the secondary again for a key NFC Sunday night game at San Francisco.
Rookie cornerback Bill Bentley also is out after sustaining a concussion in a 27-23 season-opening win against the Rams.
Delmas is recovering from left knee surgery, while Houston has an ankle injury. Drayton Florence replaced Houston, John Wendling started for Delmas and Jacob Lacey in place of Bentley.
49ers running back Brandon Jacobs is out for the second straight week with a left knee injury and so is wide receiver and return man Ted Ginn Jr. because of an injured right ankle.
San Francisco's first-round draft pick, wide receiver A.J. Jenkins, was inactive for the first time.