A reporter asked head coach Kyle Shanahan on Friday about a report that cornerback Richard Sherman would miss four weeks due to his hamstring injury. That was news to Shanahan, and probably the rest of the media in the room.

"I haven't read that report yet, but I hope not," Shanahan responded. "I hope it's week-to-week. No, that's news to me."

The reporter may have gotten his players mixed up. A report did come from Ian Rapoport of NFL Network that a 49ers defender will miss four weeks due to a hamstring injury, but it wasn't Sherman. Rapoport was reporting on defensive end Dee Ford.

That report sounds about right, based on the head coach's response when later asked about Ford.

"When you have a hamstring (injury), it can be anywhere from two to four weeks," Shanahan explained. "I would be not very optimistic about next week (vs. the Los Angeles Rams), but hopefully we can get him back before, hopefully, the playoffs. But no, that's usually the timeline it lasts with a hamstring."

The timeframe means the pass rusher could miss the rest of the regular season and might not be ready to play until the second round of the playoffs.

Of course, that isn't as big of a deal if San Francisco holds on to the NFC's best record or stays in the top two because that will earn the 49ers a first-round playoff bye. The team hosts the Atlanta Falcons this weekend and then the Rams in Week 16 before traveling to CenturyLink Field for a rematch against the Seattle Seahawks to close out the regular season.

Ford seemed surprised by the timeframe reported by Rapoport when asked by reporters.

"Four weeks? We are day-by-day right now," the veteran pass rusher said on Friday. "We don't want it to be a recurring thing. Hamstrings are tricky."

Ford suffered his hamstring injury this past Sunday against the New Orleans Saints. It was just one of several injuries the 49ers endured during the game. The team has lost defensive tackle D.J. Jones for the season due to a high-ankle sprain and center Weston Richburg due to a torn patellar tendon.

Sherman has been ruled out for Sunday but sounds optimistic he'll play next week against the Rams. Cornerback K'Waun Willians (concussion), safety Jaquiski Tartt (ribs), and defensive lineman Jullian Taylor (elbow) have also been ruled out against the Falcons.

Ford has recorded 14 tackles, 6.5 sacks, a pass defensed, and two forced fumbles through 11 games this season.