SANTA CLARA >> Safety Talanoa Hufanga is cleared to return to the 49ers’ embattled defense as soon as Sunday’s game against the Chicago Bears.

Missing from that defense for a third straight game, however, will be defensive end Nick Bosa, who was downgraded to out on Saturday because of a lingering oblique injury. Bosa has not practiced the past three weeks, nor has left tackle Trent Williams, who was ruled out Friday by the 49ers (5-7).

Left guard Aaron Banks will miss a second straight game because of a concussion, being downgraded from questionable to out.

While Hufanga was officially activated off the injured reserve list, the 49ers moved running back Jordan Mason (ankle) and special teams ace George Odum (knee) onto IR.