SANTA CLARA, Calif. (AP) — The emotional lift of Ricky Pearsall's return to the field 50 days after he was shot lasted less than a half. Then the San Francisco 49ers had to deal with some more bad news at receiver.

Brandon Aiyuk went down with a right knee injury in Sunday's 28-18 loss to the Kansas City Chiefs that coach Kyle Shanahan fears is a season-ending ACL tear. Shanahan said the team was waiting for confirmation from an MRI scheduled for Monday, but the expectation is that Aiyuk will miss the rest of the season in the latest injury blow to a San Francisco team already missing All-Pro running back Christian McCaffrey and other key players. “I know a lot of teams deal with that,” Shanahan said about the spate of injuries.

“Not every team, but we’re dealing with it hard right now. It got worse today. It’s tough.

” Aiyuk got hurt late in the first half when was hit on the knee after making a catch in the red zone. He stayed down for a few minutes before being carted to the locker room and was quickly ruled out for the rest of the game. Aiyuk, who signed a $120 million, four-year extension in late August following a lengthy contract “hold in,” has 25 catches for 374 yards this season.

He was a second-team All-Pro last season when he had 1,342 yards receiving. San Francisco was already without two of its other top receivers with Jauan Jennings sidelined by a hip injury that is not expected to be long-term and Deebo Samuel dealing with an illness that limit.