San Francisco 49ers running back Marcus Lattimore, who never played an NFL game after suffering a devastating knee injury in college, is planning to retire, according to ESPN on Monday.

Lattimore’s agent, Michael Perrett, told the NFL Network that no decision had been made and Lattimore is still weighing his options.

Lattimore, 23, was not with the team during Sunday’s home game against the St. Louis Rams.

“Did not see Marcus,” 49ers coach Jim Harbaugh said after the game in response to Lattimore’s absence. “I’m sure we’ll have an announcement about that.”

The 5-foot-11, 220-pound Lattimore spent the entire 2013 season on the non-football injury list and remains on that list this season.

Lattimore began practicing last week and was hoping that he would be able to play later this season.

During his time at the University of South Carolina, he back suffered serious knee injuries in 2011 (tore the ACL and MCL in his left knee) and 2012 (tore every ligament in his right knee and dislocated the kneecap).

Lattimore was a fourth-round draft pick of the 49ers.