A key injury on the offensive line has played a critical role in the San Francisco 49ers' three-game losing streak, and they will resume the season in Week 10 with a different member of the front on the sideline.

Two of the 49ers' three defeats have come with All-Pro left tackle Trent Williams absent because of an ankle injury. San Francisco is hopeful Williams be able to practice when they return from their bye week next Monday.

However, Williams won't have his running mate on the left side with him for a tough road game against the Jacksonville Jaguars. Head coach Kyle Shanahan revealed guard Aaron Banks has turf toe and will be out for "a few weeks" after suffering the injury late in Sunday's loss to the Cincinnati Bengals.

"Yeah, with turf toe, you never know," Shanahan said on his Monday conference call. 

"So they told me it should be a few weeks, is what I got here. I know that's a little vague, but I would say that means at least three weeks.

"I know I was told he did it on the second to last drive. I haven't gotten to speak with him personally, so I'm not sure which play it was on, but he didn't report it until after."

A three-week recovery timeline would see Banks miss two games, the Week 10 meeting with the Jags and the subsequent home game with the Tampa Bay Buccaneers. Jon Feliciano will likely step in at left guard and provide a dependable veteran presence at that spot.

On the defensive side, 49ers linebacker Dre Greenlaw is day-to-day with a shoulder strain.

"I know it was bothering him," Shanahan said. "It's been bothering for a couple of weeks, and I just know that it got worse during the game."

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