I had a guy like that, as a senior his ATH/DEF was 83/94 at D3. He also had SPD in the 50s. He was below average everywhere else (not terrible, but not good either) and was an absolute shutdown defender that warranted starting. He held the leading scorer in the nation to a season low 8 points, 5 of which didn't even come while he was on the court. (the scorer shot 1-9 against him).