Jimmy Smith, Lardarius Webb, Matt Elam, Will Davis, Asa Jackson, Terrence Brooks.
The above could easily be thought to be a list of the starting secondary for the Ravens at some point. It's not. It's a list of the Ravens defensive backs who've missed a minimum of two games due to injury since the beginning of the 2014 season.
This is a large portion of the reason the back end of the defense has been just terrible for the past calendar year. Jimmy Smith, potential Pro-Bowler, missed the playoff game against the Patriots. That alone could have been the difference between the Ravens' loss in the Divisional round to the eventual Champions (They-Who-Shall-Not-Be-Named) and going to the Super Bowl again.
Ozzie Newsome has a well documented propensity for drafting a lot of defensive backs (almost as much as he likes grabbing folks from his alma mater, Alabama.) They just keep breaking. The last two seasons has just provided a ridiculous sample of it. Both Smith and Webb have extensive injury histories, and while both have tremendous ceilings on their ability (and both have shut down top receivers when called upon in the past, though not consistently) both are also glass cannons. They wreck opposing schemes by eliminating receivers--until some part of themselves breaks.
Yet, even knowing this, Ozzie elected to let Torrey Smith walk, draft the practically fictional Perriman (have you seen him on a field? Does he exist?) and in the long run force Harbaugh to go with Shareece Wright as one of the starting corners last Sunday.
That went well.
In terms of drafting defensive backs, Ozzie has a great record for talent. Reed, McCalister, Landry, Smith. Yet all of them have been prone to injury to some degree--all missed significant time from injury in at least one season. This pattern has continued, even into the lower echelon of 'backs he's picked--Asa Jackson, for instance, is very talented, but turning quickly seems to make his knees snap like toothpicks.
Conversely, the Wizard of Oz has been terrible at selecting receivers in the draft with any extended success. The wide receivers who've had more than one good season: Torrey Smith.
End of list.
This is the one area I would question Oz the Great and Powerful: wide receivers. In hindsight Ronald Darby, the corner drafted in the 2nd round by the Bills, would have been a far safer choice. Probably fictional Perriman might someday become a fantastic receiver. But right now Darby is playing near a Pro-Bowl level as a rookie, and Ozzie's wide receiver record remains untarnished.