Lions defensive coordinator Gunther Cunningham had a very clear message to his secondary when he met with them for the first time this offseason.
Cunningham laid out a clear mandate. He told them injuries weren’t allowed this year.
“We’ve really explained the facts of life to them,” Cunningham said of that meeting. “I told them about a philosophy that we play violent defense, aggressive, between-the-lines, honest, fair and we’re going to cover.
“But the most important thing is that we’re available and accountable through the season. We can’t have injuries.”
The two biggest injuries to the unit last year were to safety 
While those injuries were certainly significant, they weren’t isolated. Lions defensive backs missed a combined 28 games last year. The number of missed practices was even more substantial, according to Cunningham.
“The defensive backs in December missed 32 to 34 practices,” he said. “The defensive line missed 33.”
It’s part of the reason the Lions went out and signed cornerback
"The last two games of the season, it was kind of a drop off," Houston said of last year’s two losses to finish the season against the Packers and Saints, when the Lions allowed 946 yards passing and nine touchdowns. "Before that, for those 13, 14 games, we were up there in the top. If we can stay healthy, we're going to surprise a lot of people."
If they can stay healthy?
The secondary depth hasn’t been good enough the past couple years to sustain a good level of play when starters have been injured. There’s just been too big of a drop off in production.
“They have the skills to (cover) but what they need to do is stay on the field,” Cunningham said. “We made a big push for that.”
The Lions seems better equipped at cornerback behind projected starters Houston and Berry with Lacey,
Overall, the Lions seem like they have more depth in their secondary, but the starters staying healthy is still the biggest obstacle the unit faces this year.
