Brown will receive $2.6875 million in guarantees, the source said. Brown's deal leaves the Panthers with two unsigned draft choices among his seven.
Brown, 21, was the 43rd pick in the 2009 draft, but he came to the team in exchange for a 2010 first-round pick the Panthers gave to the San Francisco 49ers. The 6-foot-2, 256-pound Brown was brought in to develop as a pass rusher.
A native of Stantonburg, N.C., he was first-team All-ACC at Florida State.
John Clayton is a senior writer at ESPN.com.