"He's been a talisman," said Rees. "He'll go down in Ospreys folklore for the way he manages himself and his disregard for his own safety. What he's done for us has been fantastic.
"When he was coming through as a young, aspiring professional, or when he was pushing Huw Bennett for the No2 slot, or in recent times as a senior British & Irish Lions international, whatever the circumstances, he's been a great Osprey.
"He's always wanted to put that shirt on and give 100 per cent week in, week out. He's disappointed he can't eek out a little bit more for the remainder of the year."
Hibbard sat out Friday night's win over Cardiff Blues and is expected to be unavailable for the remaining five games in the RaboDirect PRO12 regular season, as well as a potential semi-final and final if the Ospreys can hold off Glasgow and the Scarlets in the race for the play offs.
His involvement on Wales' summer tour of South Africa is also uncertain, although Rees admits that he hasn't yet given up all hope of seeing Hibbard in action again sooner rather than later.
"He needed that surgery pretty quickly for his long-term future," added Rees, who has seen the 30-year-old rack up 175 appearances for the Ospreys since 2004.
"I don't know the timeline of a comeback but we're led to believe that it could be pretty speedy, especially given his recovery rates in the past and how durable he is. We'll never say never in terms of our shirt."