The Cowboys have signed 34-year old inside linebacker Zach Thomas.  Thomas missed much of last season due to concussions but he played well when healthy which indicates that he still has some gas left in the tank.  Thomas played in 5 games last season for the Dolphins and he made 52 tackles, defensed 2 passes and had 1 sack.  Thomas has now played in 168 games in his NFL career and he has made 1,642 tackles, defensed 65 passes, forced 15 fumbles and intercepted 17 passes……four of which he returned for TDs.  This was a good move for the Cowboys who will likely start him at middle linebacker as long as he stays healthy.