At 6-foot-4 with long arms, athleticism, and the ability to really score going to the rim, Thornwell was dominant all summer long with Team United, and that led to him becoming an elite five-star recruit.
Martin and his staff tailed the Lancaster, South Carolina native all summer long and now he has a commitment.
"He chose South Carolina," said Thornwell's uncle DaJuan. "He wanted to stay home and be a catalyst for the university."
DaJuan continued, "He has a lot of respect for the coaching staff and he wanted to go where he can be Sindarius Thornwell and not next somebody else."
Oak Hill Academy Head Coach Steve Smith added this about the pledge.
"He has been leaning to South Carolina since last week," said Smith. "I think he just felt strongly about playing in state and close to home. He also trusts Frank Martin."
This commitment is the second in the 2013 class, as Thornwell joins three-star center Desmond Ringer. Also South Carolina locked up high level 2014 point guard Marcus Stroman, who like Thornwell is a native of South Carolina.