San Francisco 49ers running back Marcus Lattimore has announced that he is retiring from the NFL. He informed the team on Wednesday about his decision.

According to the Associated Press, Lattimore’s decision to retire is a result of two serious knee injuries he got while in college. Two years ago while at South Carolina he blew out his right knee. He has been trying to make a come back. However he decided that his knees might not hold up for an entire season.

''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. 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. Unfortunately, getting my knee fully back to the level the NFL demands has proven to be insurmountable. I am grateful for the entire 49ers organization. Their decision to draft me was the realization of a lifelong dream to be an NFL player, and I cannot thank them enough for believing in me and for doing everything in their power to assist in my recovery. I will always be a 49er!''

Lattimore was the 49ers fourth round pick in the 2013 draft. He was compared to Hall of Famer Earl Campbell and was considered the best backfield prospect since Adrian Peterson. However he hasn’t played in an NFL game due to the knee injuries. Last year, which was his rookie year, he was on the injured reserve list. The 49ers have paid Lattimore his full $825,000 salary and won’t seek repayment of his $300,584 signing bonus, according to NFL.com. Lattimore has a $1.7 million insurance policy which he has a good chance of collecting.

On Wednesday and Thursday of last week Lattimore practiced for the first time. He sat out on Friday. He was eligible to return after week 6, but decided that he wouldn’t be able play long term.