Ospreys finished the season comfortably in fifth in the RaboDirect PRO12 table with an 11-point cushion over sixth, but four points shy of breaking in the top four and reaching the play-offs.
Defeat in Italy to Zebre in their penultimate fixture of the season effectively put paid to their hopes despite a comfortable 45-20 last day victory over Connacht.
Leinster, Glasgow Warriors, Munster and Ulster are left to battle it out in the play-offs while Ospreys look ahead to ensuring they are in the mix this time next year.
And assistant coach Rees insists the development of youth will not be lost on the recruitment drive of the 2010 and 2012 RaboDirect PRO12 champions.
"There were seven or eight young professionals in that group, we'll drip feed a few more in year on year while trying to retain the best Welsh talent and recruit some smart overseas players to supplement what we've got," Rees told the club's website.
"I'm a pretty half-full kind of guy. We've said about the rebuilding process that's there and I don't think anyone can underestimate what we have lost, and what we are losing, in terms of experience and personnel.
"We are not going to be perfect, we are still going to get the odd blip on the horizon, but we will work our damnedest."
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Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland