Star Lotulelei, one of the elite prospects for the 2013 NFL draft, will not be allowed to work out Monday at the scouting combine after an echocardiogram revealed that the former Utah defensive tackle has a heart condition that requires more testing.

Lotulelei's agent, Bruce Tollner, confirmed to ESPN's Joe Schad that the first team All-American had an abnormal test result as part of his physical and will visit a specialist this week.

Tollner told The Associated Press in an email that Lotulelei would not take questions regarding the diagnosis yet. The Tonga native was scheduled to fly to Utah on Monday night, Tollner said.

Lotulelei was discovered to have an abnormally low Ejection Fraction, detecting that the left ventricle of his heart was pumping at only 44 percent efficiency, sources said. The normal range is between 55-70 percent efficiency.

The 6-foot-2, 311-pound Lotulelei will undergo further testing in Salt Lake City in an effort to seek more clarity with the condition, a source said. If it's a confirmed chronic condition, medical experts consider it an indication of possible heart damage.

Tollner said Lotulelei was asked by combine officials not to participate until consulting a specialist. Lotulelei still will be interviewed by NFL teams in Indianapolis and plans to participate at Utah's Pro Day on March 20.

Lotulelei is the No. 1 overall player as ranked by Scouts, Inc., and has been rated as a top-5 draft prospect by ESPN draft experts Mel Kiper Jr. and Todd McShay.

ESPN's Joe Schad contributed to this report.