Outburst: San Francisco 49ers wide receiver Brandon Aiyuk terminated his contract following a heated confrontation with management.

Aiyuk’s injury compounds the growing challenges for Shanahan.

San Francisco 49ers wide receiver Brandon Aiyuk is expected to miss the remainder of the season due to a suspected torn ACL suffered during Sunday’s 28-18 loss to the Kansas City Chiefs.

Aiyuk, who signed a four-year, $120 million contract extension in August, was hit late in the second quarter by two Chiefs defenders and left the field for the locker room.

Niners coach Kyle Shanahan commented, “It looks like a torn ACL, but we don’t know for sure. I’ve been wrong before, so let’s hope for the best.”

Tight end George Kittle expressed his disappointment, saying, “It sucks. I love Brandon Aiyuk for the energy he brings and his skills on the field. He’s an incredible player, and you can’t really replace one of the best receivers in the NFL.”

This injury adds to the challenges facing San Francisco, which is struggling this season.

The 49ers were already short-handed against a Chiefs team dealing with its own health issues, but Andy Reid and Patrick Mahomes managed to find a way to win.

In contrast, 49ers quarterback Brock Purdy completed 17 of 31 passes for 212 yards and two rushing touchdowns, but he also threw three crucial interceptions that Mahomes capitalized on.

“We didn’t do much well on offense,” Shanahan remarked. “I know Brock would love to have those three picks back. He’s had an incredible season, but today just wasn’t his day.”

The loss, a rematch of February’s Super Bowl LVIII, which the Chiefs also won, drops San Francisco to 3-4, dimming their playoff hopes.

On a positive note, Ricky Pearsall made his debut just 50 days after being shot in an armed robbery attempt in downtown San Francisco. Pearsall, who caught three passes, said, “It meant everything to me considering all the adversity I faced this past month. It felt great to be out there with my teammates again.”