COLUMBIA, SC (WIS) - The news is still sinking in that former Gamecock football star Marcus Lattimore is retiring from the NFL.
The running back made the announcement Wednesday because of knee injuries from his days at Carolina.
It didn't take long for number 21 to become a star running back at the University of South Carolina and one of the top college players in the country.
But the first big hit to Marcus Lattimore's career came in his sophomore year.
"Marcus tore his ACL at the Mississippi State game," said Dr. Jeffrey Guy with the University of South Carolina.
Lattimore also tore his MCL.
"That's a big injury to come back from and it involves letting one ligament heal before we even did surgery," Guy said.
Lattimore was back on the field the next year but the hits kept coming.
"His knee was out of place when I first walked up to it," Guy said. "It's one of the worst. He had basically 8 or 9 structures what we actually had to either repair or go back and reconstruct. So he really only had one major ligament group left."
Lattimore worked hard on rehabilitation, and in 2013 was drafted by the San Francisco 49ers.
"The reason he got as far as he has come is because he is dedicated to the things that he does," Guy said.
Unfortunately, Lattimore never played a game for San Francisco.
"Trying to get somebody back not only just to running and cutting is a big deal in itself, but, I'm sure Marcus wants to get back to the Marcus of old, and that's his goal," Guy said. "I think he probably got close, and probably decided he wasn't at the level he wanted to play at."
Guy said Lattimore was lucky no nerve or blood supply damage was caused during the injury.
Some patients actually have to have part of their leg amputated due to the injury, Guy said.