Opposing AFC North teams will have an easier time running the ball in 2015. The Lions traded for stole Ngata (and a 7th round pick) from the Ravens, giving 4th and 5th rounders for the big man. The Ravens, who were barely under the salary cap in 2014, felt compelled to pull the trigger on the trade.
I feel the Lions definitely got the better of this deal. They gave up pretty much nothing for a Pro Bowl DT/NT and filled the void left by Suh. The Ravens get some okay picks and about $8 million in cap relief.