SANTA CLARA, Calif. (AP) - San Francisco 49ers quarterback Jimmy Garoppolo underwent reconstructive surgery on his injured left knee.

Coach Kyle Shanahan said Garoppolo had the operation to repair a torn anterior cruciate ligament on Wednesday. Shanahan said he didn't know whether any additional damage needed to be repaired or know whether Garoppolo would be recovered in time for the offseason program next spring.

Garoppolo injured his knee on Sept. 23 in Kansas City when he tried to plant and cut up field instead of running out of bounds late in a loss to the Chiefs. Garoppolo is in the first season of a five-year, $137.5 million contract.

His injury dealt a serious blow to the 49ers (1-3), who are now going with C.J. Beathard at quarterback.