All stats are noisy with the amount of data we have in a college basketball season, but On/Off is one of the better ones we have, especially when it’s been adjusted for shooting luck.
But either way his Net Rating On/Off was -4.5. Those ratings you are giving I am assuming are from CBB Reference which aren’t team ratings, they are individual calculations. I’m looking at the team ratings when he was on compared to when he was off during conference, and he was a clear net negative overall