Yes, there was. But the number was retired in 1967, in honour of K.C.Jones, who was a legendary player, playing alongside greats like Bill Russell and Sam Jones in one of the Celtics' most unforgettable eras; he later went to become a very successful coach, and was enshrined in the Hall of Fame in 1989.
Chris Babb is number 52 on the Boston Celtics.
Avery Bradley is number 0 on the Boston Celtics.
Brandon Bass is number 30 on the Boston Celtics.
Chris Johnson is number 12 on the Boston Celtics.
Gerald Wallace is number 45 on the Boston Celtics.
James Young is number 1 on the Boston Celtics.
Jared Sullinger is number 7 on the Boston Celtics.
Jeff Green is number 8 on the Boston Celtics.
Jerryd Bayless is number 11 on the Boston Celtics.
Keith Bogans is number 4 on the Boston Celtics.
Kelly Olynyk is number 41 on the Boston Celtics.
Kris Humphries is number 43 on the Boston Celtics.