They lose Rowe, Carter, and Blechen. So only one DB and the two safeties (that will hurt).
But they get Porter back (would have been best CB) and Godfrey has played a lot of games cause Carter has been injured.
They keep all of their LBs. They lose Orchard, which is a huge loss. So they return 7 on defense and two of those are being replaced by guys that have a lot of experience.
On offense they lose Tonga, Dres, and 2 OL. So they return 14-22 players. That isn't very senior laden this year as you said it was.