The exclusive rights free agent who can also play cornerback signed Wednesday. Terms weren't released.
Ball has played in 28 games, including three starts, over three seasons. He is listed as the starter at free safety.
A seventh-round pick out of Illinois in 2007, Ball has 26 tackles and five pass breakups and has been a key special teams player.
Hamlin was released this month after his numbers dropped off from career highs of 102 tackles and five interceptions in 2007, the first of his three seasons in Dallas.
Copyright 2010 by The Associated Press