The Lions, who had the best record in the NFL at 15-2 before losing in the divisional round, added cornerback D.J. Reed, and re-signed two of their top defensive free agents in linebacker Derrick Barnes and edge rusher Marcus Davenport. Plus, they have star edge rusher Aidan Hutchinson back from a broken leg.

Philadelphia did most of its heavy-lifting last week, signing Saquon Barkley to a historic contract extension and re-signing All-Pro linebacker Zack Baun. While Baun is back, the Birds are expected to lose some of their free agents.

Trends are emerging as the official signing period begins. Here's a look behind the scenes at teams making big moves and those that aren't.