It has been well-documented that the Lions are among the NFL franchises that have used man coverage on defense the most this season. 

As perhaps a byproduct of the man-to-man philosophy, the Lions and defensive coordinator Paul Pasqualoni have heavily utilized "shadow" coverage against opposing wideouts.

In case you are unfamiliar with the term, shadowing is when a defensive player will follow or travel across different formations with an individual wideout or tight end.

Using Pro Football Focus' shadow-cover matrix chart, the Lions have shadowed at least one opposing wide receiver in seven of their ten games in 2019. 

The only team which has deployed a shadow in more games has been Matt Patricia's former team in the New England Patriots.

On the opposite end of the spectrum, there are 12 teams that still haven't shadowed a receiver yet this year.

Despite the Patriots shadowing in nine games compared to seven for the Lions, Detroit still has had more individuals lock on to one man over the course of the season. 

It means that the Lions don't just have their top corner travel with the opponent's top receiver, but their second and third option as well. 

The Lions, in fact, have had a defensive back shadow a receiver on 19 occasions -- most in the NFL this season.

Going into Week 12, Darius Slay has shadowed in four games, Justin Coleman and Rashaan Melvin six times each, Mike Ford twice and Tracy Walker once. 

The strategy was working decently at the start of the year. 

Going against the likes of Philip Rivers, Carson Wentz and Patrick Mahomes, the Lions had the sixth-best passer rating against -- 80.3 -- through Week 4. 

Many felt, including me, that the Lions' secondary was the underrated strength of the team. Boy, did that change quickly.

In the last five weeks, the Lions have allowed the highest passer rating against (125.50), the most touchdowns (16) and the second-most yards (1485) in the NFL.

Not all of this falls on the defensive backs, however. 

Detroit's non-existent pass rush and the fact that its linebackers have struggled in coverage have made the numbers look a lot worse.

Nothing is really working right now with the defensive scheme, but a staple of the defense has been its man-to-man coverage. 

It has worked well for one team this season -- the Patriots -- and has been disastrous for another -- the Lions.

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