Brown, the 43rd pick in the 2009 draft out of Florida State, lasted only two years with the Panthers, recording six sacks in 28 games, including just three starts.
He played three games for the Chargers in 2011 and was out of football last year after being released before the season by the Lions.
Brown, who worked out for the Eagles in early December, last played on Nov. 27, 2011, in a game against the Broncos for the Chargers. His last sack was Dec. 12, 2010, when he had 1 in a game against the Falcons for the Panthers.
Brown, 25, was a stud at FSU, where he recorded 23 sacks in three seasons, including 13 in 2008.
The Eagles on Wednesday also agreed once again to terms with cornerback Trevard Lindley, who is now in his third stint with the team. Lindley, a fourth-round pick of the Eagles in 2010, played in 12 games for the Eagles as a rookie, including the playoff loss to the Packers.