Stops is a statistic developed by Dean Oliver (who wrote the book on most of this stuff), summarized here: http://kenpom.com/blog/index.php/weblog/roster_attrition_by_conference/

You’re right in that guards generally have fewer Stops than big men, but I haven’t seen a distinction between point guards and shooting guards. In any event, Thompson’s Stops numbers are low even by guard standards. But Stops is an imperfect statistic (it doesn’t consider fouling, or lack thereof, for instance), so it’s entirely possible it’s missing contributions from Juice.