It wasn't the statistical issue. It was the fact that he was overmatched, and the scouts noticed, plus the fact that Grady didn't look overmatched, and not giving him a spot meant losing him. They couldn't give less of a s*** about spring stats, but they have a scouting team looking at guys and identifying weaknesses from the get go. As a guy who's said numerous times he worked as a scout, i'm surprised you don't see it from this point of view.
Basing anything on a sample size as small as ST is, well, pretty stupid.