Brian O'Driscoll feels Ireland will miss Jamie Heaslip at next year's World Cup and believes the retired number eight was never properly appreciated.
Heaslip announced Monday he was calling time on his career at age 34 due to a lower-back injury that has kept him out of action since last March.
Heaslip won 95 caps, three Six Nations titles and the 2009 Grand Slam, and played alongside O'Driscoll with Leinster and the British & Irish Lions.
"I know lots of people really, really rated him but I don't think people truly understood his value," said O'Driscoll, who was speaking in Monaco his role as a Laureus ambassador.
"He's a big-game player. He always turned up for big games, always. I never saw him play a sub-standard performance in a game where it really counted.
"He was a very savvy rugby player. He cleaned up an awful lot of messy stuff -- good link player, great athlete and an unbelievably good professional. He is a big loss.
"Ireland are in good shape in that position but what you don't see is that rugby intellect in every player. I think he was one of the rare ones that he could put it all together. He had a real winning mentality.
"He is absolutely a loss for Ireland -- to not have him in their 30-man squad for the World Cup, for me, will leave a little bit of a dent.
"A great opportunity for other guys but I've a lot of time for Jamie as a teammate and as a player he was someone that you wanted in your team. I felt we were stronger for having had him in our team."