Plugging the holes: AFC North

When the Steelers lost Troy Polamalu in 2009, their defense went downhill. Doug Benc/Getty Images

As we near the draft, Football Outsiders is taking a look at the major holes in the roster of each NFL team by division. Monday, it takes a crack at the AFC North.

Baltimore Ravens

Biggest Hole: Defensive Depth

Baltimore seems to have all of the pieces in place: a young, promising quarterback, a trio of talented receivers and the third-best defense in the league. While the postseason did not go quite as planned, the team seems poised to improve substantially and seize the AFC North next year. Yet one statistic is particularly troubling: Baltimore finished 26th in adjusted games lost last season. (AGL measures effectiveness lost to injury, both when starters miss games and when they play hurt).