CD3 (not sure what number he'll take there...might be CD24 or CD33!) is one of the best Man Coverage defenders in the league. No questions asked.
* Put him in Press Man or Bump & Run, In-phase, and he's elite.
* Put him in Off Man and he's solid but less good.
* Put him in Off Zone and ask him to Click & Close and he's ok (he's improved dramatically).
* Ask him to play Bail/Out of Phase in like Match Quarters or Cover 3 and he's rather JAG-ish.
The issue on our team is that Coach Bowles has done the same things he's done everywhere. Over time, he's evolved to play overwhelmingly that 3rd and 4th bullet point...same thing he's done everywhere else. The issue is Davis (and Dean to a lesser degree) is excellent at the first two bullet points, but totally replaceable at the latter two. And we're seeing stacked injury concerns. Last 3 years the median # of snaps for the top 30 CBs in snaps in the NFL is a hair under 1000 Snaps per Reg Season. Davis is a hair over 70 % of that. That is a ton of missed snaps.
So you're getting the guy I mention above + a solid, willing tackler and run support player + a player who can diagnose perimeter screens and spill the play to help or make the play.
For us, the injuries + averageness at various Zone responsibilities make him expendable unfortunately (loved the pick, loved the player, but the fit became weird as the scheme evolved away from his skillset). So if you're saying that your Lions are playing a ton of Press and Off Man (I'm only vaguely aware of your scheme tendencies so I'll defer to you), then you got a very good player (possibly elite pending % of Press Man snaps)..but he gets nicked and misses a lot of snaps...so good luck there!
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TLDR, I think this was a good move by Licht. Getting a top 100 pick (about 110 draft value) for a 70 % snap playing CB who is increasingly a weird fit + needed salary shed and some cap space - a pair of 6th rounders (maybe 25 draft value) - escalation of dead cap that will have to be distributed = Net Win IMO. And, again, I say this as someone who loved the pick and the player/teammate. Good luck CD3. Might see another Super Bowl with the Lions.