Hopes that an MRI would prove negative were dashed Monday night with a report that San Francisco 49ers wide receiver Mario Manningham is lost for the rest of the season and playoffs with a torn anterior cruciate ligament and posterior cruciate ligament in his left knee.

Manningham suffered the injury in the third quarter of Sunday’s 42-13 loss to the Seattle Seahawks. He was tackled low by Seattle linebacker Leroy Hill and fumbled. Manningham left the team’s locker room after the game limping and using crutches.

Manningham had 42 catches for 449 yards and one touchdown for San Francisco (10-4-1), which is already assured at least a berth in the NFC playoffs.