This past season was Oden's first as the Saints' secondary coach. Before that, Oden was the assistant secondary coach to Dennis Allen. Oden took over the secondary after Allen left the Saints to become the Denver Broncos' defensive coordinator.
Most of the time, coaches do not leave a team unless they are to be promoted to a higher position with a different club. However, there are cases where a coach will leave to take the same job and, obviously, this is one of those cases.
The fact that Oden has left the Saints is not a troublesome matter. The most likely reason for this is because it is not guaranteed that the new Saints defensive coordinator will keep the previous defensive position coaches.
Oden may have felt that was not going to be in New Orleans next year because of a new defensive coordinator and decided to take an opportunity that came up. Things like this will happen, especially when a team experiences as much success as the Saints have in recent years.
New Orleans has a lot of leadership on defense and in the secondary. Players like Jabari Greer and Roman Harper are experienced enough to keep that group together. The younger players in that corps, such as Patrick Robinson, Malcolm Jenkins and Johnny Patrick, will be fine as well.
Whoever the coach the Saints bring in to take over the defense will likely bring a couple of his guys with him.
Thus far, in the short and unofficial NFL offseason, the Saints have lost a coordinator and two positional coaches. It seems likely that offensive coordinator Pete Carmichael may get hired elsewhere, and offensive line coach Aaron Kromer may be gone before all is said and done.
By the time the 2012 regular season starts, the Saints may be taking the field with as many as five to six new coaches. The Saints may have a new defensive scheme and could have a couple different key coaches on offense.
However, the most important factor is that the head coach is still Sean Payton, and as long as that stays the same, then the Saints will be just fine.