Interesting move, they must like some of the younger Edge/DEs. They freed up even more cap space by releasing Attacochu. 

Pennel was signed by the Bears a few years ago, but never made the team. Seems like just another body for the D-Line.

No reason to keep a bottom of the roster player with no upside.  At least give the practice snaps to someone with more upside and see what they do with it.  

Pennel actually spent time on injured reserve during TC IIRC and then got released.