From SB Nation.com:
We have awful news to pass along. On Sunday morning, Gaines Adams of the Chicago Bears was taken to the emergency room in Greenwood, South Carolina, and later pronounced dead. The cause of death has not yet been reported.
Here's some more from Windy City Gridiron.
The No. 4 overall pick in 2007 was traded by the Buccaneers to the Bears during the season for Chicago's 2010 2nd round pick. He was often left inactive by the Bears and only had 7 tackles in 10 games for them.