I have been saying for a while now in other areas that the key to solving this secondary (and Chung's performance) revolves around finding a solid Free Safety. Let's analyze our secondary, briefly:
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Cornerback
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* Kyle Arrington - Good in intermediate coverage, fails when asked to play perimeter; will be best served as a Slot CB.
* Marquice Cole - Core Special Teamer; Emergency Slot CB.
* Alfonzo Dennard - Well-rounded CB. Can play slot, though not overly agile. Better in man to man coverage on the outside; has the makings of a solid #2 CB, should be given more starts.
* Ras-I Dowling - Has height, length, speed, and agility to excel in press coverage and be a potential shut down corner. Injuries and lack of playing time have not allowed him to flourish, however. Weak in zone coverage. Athletic enough to play Safety.
* Devin McCourty - Our best CB (and arguably best Safety), is weak in man to man coverage. Excels in zone, needs to have the play in front of him so he can use his instincts to attack and be aggressive.
* Sterling Moore - He has had a few memorable plays, though is really a JAG. Can be emergency Safety. Average in all areas, can be beaten easily.
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Safety
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* Patrick Chung - Physical in the box safety who can cover tight ends and running backs if allowed to play close to the line. Has speed and good instincts, when asked to blitz, he usually disrupts.
* Nate Ebner - Special Teamer.
* Steve Gregory - An intelligent safety who can play any role (SS, FS, CB), he is best served as a FS. Knocks are, however, that he is usually late to make a play, misses tackles.
* Tavon Wilson - A large Safety that can play any role similar to Gregory. Has played FS and SS. Best used as an in the box Safety like Chung to kill Tight Ends and Running Backs. Can develop as a FS due to CB experience.
Sorry for the clutter above. I just wanted to point out some general strengths and weaknesses of our DBs. If Chung is to be the leader of this unit, it NEEDS to be built around him. He is our Polamalu (In style of play, not skill). He needs his Ryan Clark (as another poster had alluded to). The choices come down to Gregory or McCourty. Gregory has been very up and down, and while McCourty has shown to do well in a FS role due to its zone type of play, he is also our best CB, and a decision has to be made.
Frankly, I would pair Chung and McCourty going forward. CB play has been down, but Safety play has been horrible. In 2010, when Chung was at his best, Sanders was still around and covered the deep field while Chung patrolled the line. McCourty can easily fill that Sanders role. Gregory, until he proves otherwise, is a backup. Wilson can develop into a solid No. 3 or potential starter.
With McCourty out at CB, we are left with Arrington, Cole, Dennard, Dowling, and Moore. Arrington is a Slot CB, he cannot be allowed to play on the perimeter, especially if the Pats shift to more man to man. The two players that excel in that coverage are Dennard and Dowling. As promising as Dowling is, however, he is injured. Again. And the coaches aren't trusting him to play, which is a shame since he was a starter last year. In Dowling's absence, Moore could be capable.
In short, I propose a backfield of:
Dennard - McCourty - Chung - Dowling; Slot CB - Arrington
In combination with a Cover 1, man to man scheme, Chung should return to form, and the secondary should be able to recover.