No injury is ever a good thing, but depending on the composition of the roster, teams are better equipped to handle injuries in certain spots than others. The Jets have a lot of talent on their roster. I am not sure there is a single player whose absence could torpedo the season if coaching strategy changes, and other players step up. Life is a lot easier with the starters in there, though. They are starters for a reason. They are the best players. Here is where I think the team would see a significant downgrade with backups.
Quarterback: Mark Sanchez had a coming out party of sorts in the Playoffs with 4 touchdowns, 2 interceptions, and a 92.7 quarterback rating. He was no Joe Flacco, getting carried by a defense. He earned his keep in January. Even more, he showed great recognition on the field. I think back to the 80 yard bomb in the AFC Championship Game where he pump faked to buy himself extra time with Dwight Freeney bearing down on him and to freeze the safety deep. The Jets are going to rely much more heavily on the passing game this year. Sanchez has the potential to join the upper tier of quarterbacks in the league. The passing game probably will not grow with any other quarterback on the roster. Mark Brunell brings some value as a veteran mentor, but it has been about a decade since he played his best football. Kellen Clemens is by all accounts one of the best people in the league, but his on field play has not been very good in his four years. Erik Ainge and Kevin O'Connell are untested. Under any of the four men behind him on the depth chart, the offense will likely have to revert back to purely ground and pound to keep the team in the game.
Tight End: The Jets do not have a pass catching tight end like Dustin Keller on the roster. He adds an extra dimension to the offense as a matchup problem for linebackers and safeties. Ben Hartsock is an excellent blocker, but that is all. He is a third tackle type of tight end. He has 28 catches and 1 touchdown in a career that started in 2004. Matthew Mulligan also looks like a big blocker. Jeff Cumberland has potential to become a player one day but is very raw. My guess is he ends up on the practice squad as a developmental player.
Safety: I like the guys the Jets have as backup safeties, Eric Smith and James Ihedigbo. I think they both have played well in subpackages given specialized roles tailored to their talents. I'm not sure how comfortable I would be with either starting. Smith is a former starter, and his warts tend to show in an expanded role. He's not very fast or athletic by NFL standards. Ihedigbo impressed me as a blitzer, but we haven't seen a lot of him in coverage. I would be a little concerned if something happened to Jim Leonhard or Brodney Pool.
Are there any positions you are concerned about a lack of depth?