SANTA CLARA -- Starting strong safety Jaquiski Tartt, who has already missed two 49ers games this season with a shoulder injury, did not practice Tuesday after leaving Sunday’s game because he aggravated the injury.
In addition, Tartt’s backup Antone Exum will not have time to clear concussion protocol before Thursday’s game against the Raiders, 49ers coach Kyle Shanahan said.
Tyvis Powell, who struggled late in the 49ers’ 18-15 loss to the Arizona Cardinals on Sunday, could get the starting assignment at strong safety against the Raiders.
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“Obviously, there are some plays, some things that he wants back,” 49ers defensive coordinator Robert Saleh said of Powell. “If Tartt is unable to go this week, he’ll have another opportunity to prove himself. We have tremendous faith in him. He’s a good football player, that’s why he’s here.”
Rookie safety Marcell Harris is expected to be activated off injured reserve to be available for the game, too.
Linebacker Reuben Foster’s available is in question due to a hamstring injury. Veteran Malcolm Smith would likely start in place of Foster.
Quarterback C.J. Beathard did not practice Tuesday, opening the possibility of Nick Mullens getting his first NFL start.
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49ers practice report
TUESDAY
Did not practice
QB C.J. Beathard (right wrist)
S Antone Exum (concussion)
LB Reuben Foster (hamstring)
S Jaquiski Tartt (shoulder)
Limited practice
RB Matt Breida (ankle)
WR Pierre Garçon (shoulder, knee)
RB Raheem Mostert (ankle)
G Mike Person (ankle)
C Weston Richburg (knee)
CB Richard Sherman (calf, heel)
T Joe Staley (ankle)
Raiders practice report
TUESDAY
Did not practice
T T.J. Clemmings (knee)
Limited practice
CB Gareon Conley (foot)
G Jon Feliciano (ribs)
WR Dwayne Harris (shoulder)
C Rodney Hudson (ankle)
DE Bruce Irvin (pectoral)
G Gabe Jackson (pectoral)
T Kolton Miller (knee)
G Kelechi Osemele (knee)
CB Daryl Worley (shoulder)