JACKSONVILLE, Fla. -- As investigators waited on Thursday for autopsy results to find out what killed a 24-year-old football player with a bright future ahead of him, the man who helped train the competitor reflected on the athlete's physical ability and personality.

Heath Benedict, an offensive lineman from Newberry College in South Carolina, had been working out in Jacksonville.

Wednesday evening, police were called to a gated community in San Jose, where Benedict's parents live. Inside the home, they found the 24-year-old lying dead on the couch.

Benedict was expected to be selected in the second or third round of the upcoming 2008 NFL Draft and had even worked out with the Jacksonville Jaguars.

"I was in shock, absolute shock. I thought they must have the wrong guy," said Benedict's personal trainer and the executive director of the Hit Center Aaron Marston.

Marston had been helping Benedict in his quest to become a better athlete and an NFL Draft pick.

Just last month, Marston led Benedict through high-intensity training to get the football player ready for the NFL combine.

"He was a phenomenal athlete -- phenomenal. We see the top tier, and Heath was right there. He had a very bright future ahead of him," Marston said.

Tragically, that future ended with Benedict's sudden death.

"I just couldn't believe that Heath, such a physical specimen, so young, could be taken so early," Marston said.

Marston said he began training Benedict in 2007 after the offensive lineman had ankle surgery. At 6 feet 5 Inches tall and 330 pounds, Benedict was big, and Marston said he was also fast.

However, what impressed Marston most was Benedict's personality.

"When he came into the Hit Center, the entire energy level raised. He was a real extrovert. He was comfortable with people around him. He would make anyone from a 9-year-old football player to a stay-at-home mom to one of my first-day trainers feel very open and comfortable," Marston said.

He said the center's trainers work with a lot of top athletes -- more than a dozen Jaguars worked out there during the off season -- but he said everyone will remember Benedict.

"It really is a tragedy … a shame. Heath is a young guy, a nice guy. He's got a wonderful family. They're all very supportive of him. He had a bright future ahead of him, and my heart goes out to his family," Marston said.