San Francisco 49ers running back Marcus Lattimore announced his retirement Wednesday, five days after experiencing soreness in his surgically-repaired right knee.

“After prayer and careful consideration, I have decided it’s time to end my professional football career,” Lattimore said in a statement. “I have given my heart and soul to the game that I love, and it’s time for me to move on to the next chapter of my life and help others.

Lattimore suffered a gruesome knee injury while playing for South Carolina in 2012. It was his second major knee injury while playing for the Gamecocks, and Lattimore opted to enter the NFL Draft the following spring.

The 49ers took a chance by using a fourth-round pick on Lattimore, knowing he would sit out his entire rookie season. Lattimore rehabbed his knee through all of 2013 and finally returned to practice last week with the hope of returning to the field this season. However, he experienced soreness in the knee on Friday and left the team to discuss his future with his family.

“I have given every ounce of my energy toward making a full recovery from my knee injury, and I have made a lot of progress,” Lattimore said. “Unfortunately, getting my knee fully back to the level the NFL demands has proven to be insurmountable.

Lattimore, 23, retires without having ever played a down in the NFL.

“This was a very difficult decision for Marcus and it was clear after speaking with him that he had put a lot of thought into it,” 49ers general manager Trent Baalke said in a statement. “He is a high-character young man who has done everything asked of him and more during his time with us and we have a great deal of respect for the strength and commitment he showed throughout the rehab process.

“It has been a pleasure to have Marcus as a member of our team and our community and we are confident that he will be very successful in whichever path he chooses to take in life. We look forward to supporting Marcus and wish him nothing but the best.”

Lattimore holds the South Carolina career records for much rushing touchdowns (38) and total touchdowns (41). He rushed for 2,677 yards on 555 carries in 29 career games.

Lattimore said he does not have an exact plan for what he will do next, beyond returning to South Carolina to earn his degree.

“Though I am proud of what I have accomplished throughout my football career, I am sincerely disappointed that it must end, but I trust that God has a great plan for my future,” he said. “I cannot say enough about the support from the Gamecock family since the first day I stepped on campus until now. I am so proud to be a part of the USC family, and I promise to always represent the garnet and black with honor and integrity.

I will also continue to work with my foundation, the Marcus Lattimore Foundation / DREAMS, to provide opportunities and platforms to benefit youth sports programs in the state of South Carolina. I am looking forward to pursuing my personal interests and helping others achieve their goals and dreams.