Former South Carolina running back Marcus Lattimore is retiring from the NFL after a brief stint with the San Francisco 49ers, having not played in a single game. It has been a sad fall for the former five-star recruit, who was a star at South Carolina, but was drafted in the fourth round after the second of two brutal knee injuries.

All he'll have made from his football career is about $2.825 million — $1.7 million from insurance, $300,000 from a signing bonus and $825,000 in salary. Since he was placed on the non-football injury list, the 49ers didn't have to pay him his yearly salary, but they did, according to Ian Rapoport. For a player with his potential coming out of high school, that was almost unthinkable, and now he will be heading back into the real world. Even if he decides to give it another go, it's clear that his most productive money-making years are behind him.

One of the NCAA's major arguments against allowing players to make money is that the best ones will have the opportunity to get paid in the pros. While this argument deprives college stars who won't make the NFL, Lattimore's situation shows that even the star players who do appear to have futures in the NFL won't necessarily realize their money-making potential.

Marcus Lattimore did a helluva lot more for South Carolina and the NCAA than South Carolina and the NCAA ever did for him. — Joel D. Anderson (@blackink12) November 3, 2014

It's not like there was no support to pay Lattimore at South Carolina. His coach, Steve Spurrier, would have gladly pitched in while he was there. South Carolina's athletic department brings in $90 million in revenue per year, so it could have afforded to pay him as well, and there's no doubt that boosters would have pitched in to get Lattimore to South Carolina in the first place. If nothing else, Lattimore should've been able to make endorsement money as a college athlete.

But instead, one of the most talented running backs in America over the past few years will not come close to his full earning potential.