Coach Kyle Shanahan said tests Monday confirmed the initial diagnosis that Aiyuk tore his ACL and would need major reconstructive surgery after getting hit on the knee while making a catch in the red zone late in the second quarter of a 28-18 loss to the Kansas City Chiefs on Sunday. Shanahan said Aiyuk also tore his MCL.

Brandon Aiyuk had two receptions for 23 yards in the first half, but it came on six targets, and Aiyuk should have easily been north of 50 yards. He had a huge drop on third down that would have added points to the scoreboard.