Sports or Sport is not a genetic term
From online Free Dictionary (medical):
mutation /mu·ta·tion/ (mu-ta´shun) a permanent transmissible change in the genetic material. Also, an individual exhibiting such change; a sport.
From Merriam Webster:
sport an individual exhibiting a sudden deviation from type beyond the normal limits of individual variation usually as a result of mutation especially of somatic tissue
From Wikipedia's entry mutant:
Previously, people used the word sport to refer abnormal specimens.
So, maybe it is not a term geneticists use, but the meaning of my use was clear. The question remains: weren't Delawares originally the result of mutations rather than a reliably repeatable process?