Marcus Lattimore Weighing NFL Future: Latest Details, Comments and Reaction

San Francisco 49ers running back Marcus Lattimore's two-year comeback attempt may be over.

His agent, Michael Perrett, stated, "No decision has been made on Lattimore's future," but Adam Caplan of ESPN reports the running back is expected to announce his retirement due to knee issues:

Jeff Chiu/Associated Press

San Francisco head coach Jim Harbaugh later spoke about Lattimore's future on Monday, via the 49ers:

Lattimore, who turned 23 last week, suffered a right knee dislocation during his junior season at South Carolina in his final collegiate game versus Tennessee in 2012. The season prior, he tore the ACL and MCL in his left knee against Mississippi State on Oct. 15, 2011, missing the rest of the season as a result.

Considered a potential first-round pick before the second serious injury, the 49ers took a chance on Lattimore in the fourth round of the 2013 draft (No. 131 overall), despite knowing it'd be unlikely he would play before the 2014 season.

The former second-team All-American (2010) sat out his entire rookie campaign while rehabbing. He returned to practice for the first time last week, opening a 21-day window for the 49ers to decide whether he would be activated this season.

It did not take long before injury issues cropped up again. 

Lattimore dealt with soreness in his right knee after practicing and was not with the team for Sunday's 13-10 loss to the St. Louis Rams. However, Matt Barrows of The Sacramento Bee reports "Lattimore is not believed to have suffered any structural damage in the knee since his return to practice last week."

"(I) did not see Marcus," Harbaugh told reporters when asked about Lattimore's status. "I'm sure we'll have an announcement about that."

Drafting Lattimore was always seen as a boom-or-bust proposition with Frank Gore, 31, on the roster. In fact, the franchise took a similar risk on a post-injury Gore in the 2005 draft (third round, No. 65 overall). The team also selected Carlos Hyde out of Ohio State in the second round (No. 57 overall) in the 2014 draft.

A bruising runner with an ideal combination of size and quickness (5'11", 220 lbs), Lattimore rushed for 2,677 yards and 38 touchdowns in three seasons at South Carolina.

For more on Lattimore's latest injury news and recovery, check out this timeline on B/R.

Follow Tyler Conway (@tylerconway22) on Twitter.