A lymphoid progenitor cell that is committed to the natural killer cell lineage, expressing CD122 (IL-15) receptor, but lacking many of the phenotypic characteristics of later stages of natural killer cell development such as expression of NK activating and inhibitory molecules. In human this cell has the phenotype CD34-positive, CD45RA-positive, CD10-positive, CD117-negative, and CD161 negative. [ http://www.ncbi.nlm.nih.gov/pubmed/12457618 http://www.ncbi.nlm.nih.gov/pubmed/15032583 http://purl.obolibrary.org/obo/go/references/0000031 http://www.ncbi.nlm.nih.gov/pubmed/15766674 http://www.ncbi.nlm.nih.gov/pubmed/11532393 ]