Head coach Kyle Shanahan confirmed Monday that Aiyuk sustained tears to the ACL and MCL in his right knee during Sunday's loss to the Chiefs, Nick Wagoner of ESPN.com reports.
Aiyuk will undergo surgery and miss the remainder of the season, ending it with 25 catches (on 47 targets) for 374 yards and no touchdowns in seven games. With Deebo Samuel suffering from pneumonia, Jauan Jennings dealing with a hip issue and Chris Conley tending to a sprained ankle, the 49ers' current healthy wide receivers on the active roster are Ricky Pearsall, Jacob Cowing and Ronnie Bell.