The San Francisco 49ers defense will be missing key contributors this weekend against the Atlanta Falcons. Head coach Kyle Shanahan joined KNBR on Thursday, and in addition to revealing that defensive tackle D.J. Jones is headed to injured reserve, said the defense would also be without two starting defensive backs, Richard Sherman and Jaquiski Tartt.

Sherman is dealing with a Grade 2 hamstring strain suffered during Sunday's win over the New Orleans Saints. It's an injury that typically requires weeks of recovery. Sherman told reporters on Thursday that he doesn't expect to be sidelined that long.

"I could play this week if we had to have it, but they're just being precautious," Sherman said, "and it will give me another week to heal. ... The coaching staff says I can't go, then I can't go, but I expect to be able to go the following game."

Tartt was inactive against the Saints after suffering a rib injury the week before in Baltimore. His injury is more of a pain tolerance issue, at this point, and the safety will get another week to recover.

"Hopefully, we can get him going next week," Shanahan said on the "Tolbert, Krueger and Brooks" show. "It's still going to be tight."

Shanahan provided an update on another defensive back, K'Waun Williams, saying he remains in the concussion protocol.

"We'll see how he comes in tomorrow," he added.

You can listen to the entire conversation with Shanahan below.