"Here are my cornerback rankings for the 2019 NFL Draft!"
Here at TDN, we like to say that rankings aren't that important. I mean sure, we'll publish our final big board before the Draft kicks off, because it's important to have a stance on how these players should be ranked. But the minute players get slotted to teams, that has a drastic effect on your Year 1 and Year 3 projections for those prospects, and subsequently your rankings
Put another way: while you may have projected Kolton Miller to be a good player with development, once he was drafted by the Oakland Raiders and put under Tom Cable's purview, you wanted off the train.
Rankings matter, but they don't matter as much as actual analysis: the description of a player's possible path to success, what that role looks like, and how his weaknesses can be protected by the team that surrounds him. Everyone would have been a bit higher on Darius Leonard if they knew he was going to be a Tampa 2 zone defender: it fits what he does well and protects him from what he does poorly.
So while cornerback rankings are objectively good and necessary, it's more important to correctly cast each player into his correct role. Byron Murphy might be your CB1, but he should only be CB1 for teams that run heavy zone Cover 3, especially from off-alignments. Greedy Williams might be your CB1, but he should only be CB1 for teams that run press-man coverage. DeAndre Baker might be your CB1, but he should only be CB1 for teams that run heavy Cover 2 and other short zones.
To understand the fits, you have to understand the traits that lend themselves to each role, as well as the weaknesses that preclude a player from filling the role with regularity. The reality is that there will be some overlap -- some players can fit multiple roles, a boon to their stock -- but these are the ideal scheme and alignment fits for the 2019 NFL cornerback class.
Zone Coverage - Cover 3
Zone corners play with their eyes in the backfield, often reading through the receiver into the backfield to diagnose common route combinations and anticipate wide receiver breaks. Zone corners must be instinctive and intelligent players who can quickly get connected to routes from that initially disconnected state -- if a player lacks the feel to space out his zone and put himself in position to respond to the route combinations, he can't be a zone defender.
Cover 3 corners specifically must have the deep speed to protect the deep third of the field, while still having the aggressiveness and recognition to close down into the flat on quick-hitting plays. Unlike Cover 2 zone corners, they can't be super aggressive closing downhill or into the sideline, as they don't have the help over the top of a deep-half defender.
The Seattle style of Cover 3 has created a false narrative that Cover 3 corners must be long, tall, and disruptive at the line of scrimmage. While that is a mold that some teams use with success (Seattle, San Francisco), other heavy Cover 3 teams (Philadelphia, Redskins) play their corners off-ball.
As such, all of these corners fit in Cover 3 schemes -- but some would benefit more from off-alignments, and others would benefit more from the press.
Zone Coverage - Cover 2
Cover 2 corners are protected from playing the deep third, as compared to Cover 3 corners, so players who aren't necessarily as fast on a straight line often fit better in this role. They are more responsible, however, for collisioning receivers in the contact window to disrupt route stems/timing, and they have to be sure to split vertical spacing concepts, so a strong sense of space and great instincts are necessary.
Cover 2 corners make their plays by reading the quick game and turning film study and instincts into anticipatory, high-risk attacks on the football. They must explode out of their click and close and have strong ball skills to track and attack, as well as the requisite physicality to rally downhill and hit to minimize YAC.
Man Coverage - Press
The press alignment maximizes the big measurable of recent corners: length. All the rage in the recent development of the position, the press alignment is utilized to disrupt releases and accordingly break timing routes, forcing the quarterback to hold onto the football for that extra half second and helping the pass-rush arrive.
Press technique isn't always found at the college level, though. Many ideal press corners at the next level are super raw, having maximized their length and strength but lacking in the patience and foot technique (press starts from the feet!) to survive against the elite receivers of college football. As such, many ideal press corners are not Day 1 picks, but late Day 2/early Day 3, as they're more so Year 3 than Year 1 starters.
Man Coverage - Off/Slot
Lumped in the slot and off-man into one group here, for a couple reasons. First: with the growth of the "big slot" role, it's becoming increasingly tougher to say "shorter corners go to the slot." If the shorter receivers aren't always going there, then the shorter corners can't also go there indiscriminately.
Secondly, slot play is almost always short zone play (a la Cover 2) or off-man coverage. It's very hard to get into the press alignment from the slot, because the sideline isn't there to help eliminate one half of the field, as it is for boundary corners. You can't really play with a shade or try to funnel the route stem one direction, because the field is wide open from the slot.
So the roles have some significant overlap, so we'll leave these two groups lumped together. The Mark Fields and Jimmy Morelands off the world likely will get pushed into the slot by traditional thinkers, but we'll see what happens when they get drafted.
These players have the physical traits and technique to fit almost any role -- or at least, they're equally good everywhere (looking at you, Julian Love). Accordingly, these will be some of my top-ranked corners, and have a high floor because they can withstand changes at defensive coordinators across their career.