GREENWOOD, S.C. (AP) — Gaines Adams, a defensive lineman for the Chicago Bears who was an all-American at Clemson, died Sunday in South Carolina, the Bears said. He was 26.

The team said Adams died Sunday morning at Self Regional Hospital in his hometown of Greenwood, S.C.

Adams went into cardiac arrest at his family’s home early Sunday morning, said Marcia Kelley-Clark, chief deputy coroner for Greenwood County. He was pronounced dead about an hour later, she said.

An autopsy conducted Sunday showed Adams had an enlarged heart, a condition Kelley-Clark said can often lead to a heart attack. But Adams’ relatives didn’t know about it.

“Nobody was aware of any kind of medical condition,” Kelley-Clark said.

Toxicology tests are being run by the State Law Enforcement Division, though drug use was not suspected as a factor in Adams’ death. However, those results probably will not be available for at least two months, Kelley-Clark said.

Adams was selected fourth overall in the 2007 NFL draft by Tampa Bay, but was traded to the Chicago Bears in October 2009 for a second-round pick in the 2010 draft. He had not been able to live up to expectations that he would revive the Buccaneers’ once-feared pass rush, having just 17 tackles and one sack in 15 games this season.

Adams fell short of the benchmark set by Buccaneers coach Raheem Morris, who said at the start of training camp that Adams would be considered a “bust” if he didn’t reach double digits in sacks.

The 6-foot-5, 258-pound defensive end was well-known among Clemson fans for breaking up Wake Forest’s field goal try and returning it for a touchdown in 2006 to defeat the Demon Deacons.

Adams said during training camp that he welcomed the challenge posed by Morris, who also called out the third-year pro after Adams began the season with lackluster performances in the first three games.

“In football you need that. Players tend to get in their own element and do things that they want to do. They need to be called out sometimes. He’s the coach. Whatever he says, goes,” Adams said in early August.

“I take it as a challenge. Being drafted fourth overall, that comes with the territory. It’s year three for me. Obviously it’s time for me to step up.”

With the Bears, Adams played brief stints on defense. He made five tackles.

“We thought the player was a quality player, and if we get him in our system with our coaches, we have a lot of confidence we can make it work,” Chicago general manager Jerry Angelo said after the Bears acquired Adams.

Bears linebacker Brian Urlacher told the Chicago Tribune that Adams’ death was “crazy.”

“I didn’t know him that well because he came in during the middle of the season,” Urlacher said. “But I did know him. I still saw him every day when I went into work. It’s just weird.

“I had a teammate die when I was in college. You just don’t know how to handle it. It’s just sad, man. It’s a bad deal.”