49ers HC gives worrying update about WR Brandon Aiyuk

Things went from bad to worse for the San Francisco 49ers in their 28-18 loss to the Kansas City Chiefs.

Wide receiver Brandon Aiyuk took a brutal hit after catching a pass from quarterback Brock Purdy. Replay showed his knee clearly hyperextending and he eventually needed to be carted off to the locker room.

San Francisco head coach Kyle Shanahan told reporters after the game that the team fears Aiyuk tore his ACL, an injury that would require season-ending surgery.

The 26-year-old signed a four-year, $120M extension in the offseason, something that the veteran wide receiver sat out of training camp for.

Aiyuk was struggling to return to his previous form that earned him the extension, posting just 374 yards and no touchdowns over seven games this year .

San Francisco will be even thinner on offense going forward if Aiyuk's injury is as serious as Shanahan fears. The team saw its other star wide receiver Deebo Samuel leave the game early with an undisclosed ailment.

It's also missing star running back Christian McCaffrey due to Achilles tendinitis in both of his calves and wideout Jauan Jennings who suffered a hip injury in Week 6.

Purdy's options on offense have been relegated to starting tight end George Kittle, backup rusher Jordan Mason and receivers Chris Conley, Ronnie Bell, Jacob Cowing and Ricky Pearsall.