This is a really great move for the Lions considering that they were in need of help at the middle linebacker position. Tulloch has been great in recent years with the Titans and has proven to be very durable.
The addition of Tulloch will likely force DeAndre Levy to the outside but having Tulloch lined up behind their tough defensive line gives their defense added balance. Jim Schwartz coached Tulloch while as the Titans defensive coordinator which should make things a lot easier for him.
This move does however make the Buffalo Bills the top suitor for LB Nick Barnett who had been rumored as a possibility for the Lions.