Rondo is 26 and will turn 27 mid-season next year.
Avery I think could emerge as a start, but he's at least a serviceable starter for the next generation--at this point requiring stars around him.
Bass I think is likely to move on.
The Boilermakers unfortunately are question marks at best right now.
Stiemer will be a 2nd-year 27yo backup when the season starts.
But I agree, if Danny doesn't bring back more than two of the Big Three and only brings in FA's in their primer or before their prime, then the team will be young next year--unless Pierce and KG are both starters.
You can't have pensioners as two of your starters and fairly call your team young.
PS Oh, and I think Dooling might be back next year as well, to augment the veteran leadership.