I wouldn't be surprised if we approached youngest 5 by next year, as I assume Hannan, Burish, and Scott will be gone (possibly a mistake to assume this). Replace Tennysson, Irwin, and Hannan with Mueller, Shauser, and Doherty (awful lot of youth there), Niemi with Groesenik; and Soctt, Burish, and Kennedy with Tierney, Hamilton, and Goldobin.
Replace Sheppard, Burish, Scott, Kennedy, and Desjardins with Hamilton, Tierney, Goldobin, Gooderow, and McGinn.
Brings the average to 26.2. Personally, I think Scott, Kennedy, and Burish will be gone, and I expect Tierney/Hamilton, Goldobin, and McGinn or someone else, to take those spots in the near future.
Burish definitely gone, Scott will be gone unless he does well somehow, and this has been confirmed as Hannan's last season I believe.