Their defense is pretty young, it seems to me:
Richard Seymour, Ty Warren, Vince Wilfork, Jarvis Green, and Rodney Bailey are all young along the DL.
The secondary is young with Asante Samuel, Randall Gay, Eugene Wilson, and recent high draft picks Guss Scott, Dexter Reid, Ellis Hobbs and James Sanders.
The LBs are a little old, but that's just one unit.