Since Kyle Arrington's singning, many have shoed him in as the automatic starter at nickel corner. Most have placed Rashaan Melvin on the back burner, probably due to his performance in Foxborough.
Granted, New England was a disaster for Melvin. However, one must look at the strategy employed. The Ravens sat back in cover four, with the cornerbacks at least 10 yards off. Yards were bound to be given up. If anything, Melvin was a solid tackler.
Melvin being the starting nickel is the ideal scenario. As a 6'2" cornerback, he has the length to play press, coupled with enough agility and fluidity to play cover 2 and cover 3 zones adequately.