Jared Sullinger has been medically red flagged by NBA doctors, according to multiple sources.

Sullinger underwent a series of tests at the NBA combine and doctors are concerned with Sullinger's back.

Doctors believe Sullinger's back issues could shorten his career and some have advised teams not to select him in the first round.

Sullinger's agent, David Falk, when reached via phone by ESPN.com said that he was not in a position to comment on the story. 

Sullinger's father, Satch Sullinger, said he believes the issue isn't that serious.

"He had a bulging area that was due to his hamstring and quads being so tight," Satch Sullinger told ESPN.com senior college basketball writer Andy Katz in a phone call Monday afternoon. "It pulled on his hip flexor and he's been taking care of it to loosen it. You can call it a red flag if you want. But it's tight hamstring and tight quads. He's been to doctors, he's doing yoga and deep tissue massage. The flexibility is helping take the pressure off the area.

"We've got nothing to hide. At this stage it's all about what they can't do. Jared is a skilled player. A two-time All-American. He can play."