With Kelly Herndon getting the axe, it seems appropriate to debut the long lost season review for Kelly Jennings. So powered by elementary geometry and the wonder that is Microsoft's paint program, onward:
Seahawks' fans, gird thy loins and keep your kvetching to a minimum, Kelly Jennings is going to get beat deep this year, more than once. As a second year corner trusted to start, that might be a tautologous statement, but Jennings is especially susceptible to the deep pass. Not because he's slow, Jennings, like Josh Wilson, has rare speed for a corner. Not because his overall awareness is weak, or that he takes plays off or that he'll be facing an unprecedented quality of opponent (well, no more than any inexperienced NFL player). In true Tim Ruskell fashion, Jennings is a heady player, a hard worker and comes from a major program, Miami. Jennings will be beat deep because it happened in college, again and again. Be it his stiff hips, his inability to leave a proper cushion in deep zone or his poor awareness when the ball is in the air, for all Jennings' speed, he has yet to be strong in deep coverage. With Deon Grant in the fold, that might be alright, though.
Ideally, a team wants elite, rounded player's without weakness, at every position, but that's never going to happen. Instead, a team must construct a good formula. A set of player's with complimentary abilities. Denver imported Dre' Bly to pair with Champ Bailey this offseason in the hopes of attaining more cover sacks from a front seven that lacks pass rush. The idea, a pair of elite corners will keep the receivers covered and the quarterback clutching and double clutching until the pocket eventually collapses. That's a way of managing one weakness with an attainable strength. Seattle, on the other hand, has only one true cover corner--and Marcus Trufant has yet to truly validate that label. John Marshall has instead constructed a potentially elite pass rush and a set of DBs and LBs who can play strong zone coverage and be opportunistic when the QB is pressured.
This formula is precisely why Seattle let a talented young safety, Ken Hamlin, go and (over)paid for Grant. Hamlin liked to play close to the line and had decent range on short to intermediate routes. He did not, however, excel in deep coverage. He bit hard on play-action, took bad angles deep and simply doesn't have the speed to track down a wide receiver in pursuit. I doubt Grant is much faster than Hamlin, but he excels at keeping the play ahead of him, therefore, when a receiver comes streaking into his deep shell, Grant is able to get a body on him when Hamlin can't. Using vectors, this little diagram might clear up what I mean:
For simplicity's sake, we'll say everyone is running 10 YPS in this diagram. When we pick up the action, Holt has run 20 yards down the field on a simple streak pattern. Hamlin is essentially parallel to Holt but ten yards to left; he starts closer than Grant, but because Hamlin trails Holt, Holt will be running away from Hamlin for the length of his pursuit. In football jargon, that means Hamlin is beat. Grant is ten yards to the left and ten yards up the field from Holt, where Holt wishes to be, and therefore Holt is actually running towards Grant. Now let's jump one second forward in time:
The result is that while Hamlin starts closer to Holt, after 1 second Hamlin is roughly 4 yards behind Holt and destined to never catch the speedy receiver. We know that because in this example Hamlin and Holt make a 45-45-90 right triangle with Hamlin's angle of pursuit equaling the hypotenuse. Meanwhile, Grant has intercepted him precisely, with both players reaching the same spot thirty yards down the field at exactly the same time. Football routes are never this simple or orderly, but the geometry holds true: A defender in zone coverage must stay ahead of a receiver with similar or better speed if they have any hope of intercepting them.
The reason for that digression brings us back to constructing a winning formula. Jennings is weak against deep passes and will let receivers get behind him, but very strong against short and intermediate routes where his excellent speed, agility and coverage skills keep him on his opponents' hip. Grant plays very deep and won't contribute a great deal against short or intermediate passes, but excels at picking up his man after he's passed the cornerback. Between the two, Seattle should have excellent short and deep coverage on the right side. That formula, unfortunately, leaves them a man down on the left. Trufant must be able to man his side competently, essentially on an island. Not every play, but for many plays and for crucial plays. The more Grant must help Trufant against the deep pass, the more often Jennings will be exposed. So, remember, as the bile is tickling you tonsils after a receiver streaks past Jennings for a score, that burn is on the whole secondary.