Who said Kelley is going to keep Mack off the floor? I'll answer that for you: you did. Not this guy.
It's extremely likely Anthony Mack isn't going to be playing much point. He'll get his minutes, but they won't be bringing the ball up the floor.
Kelley is still going to get his minutes. He hasn't done anything but pile up assists, limit the turnovers, hit his free throws, be a defensive pest, rebound well for a guard, finish second on the team in three point shooting percentage, lead the team in assists/turnover and close to(if not) leading the team in +/-.
Anthony Mack will get his minutes too, if he plays. He might not play if he's missed most of camp and the beginning of the season with injury. He might redshirt. It's a nice luxury to have: put a redshirt on him, or make the decision to pull his shirt for the post-season, if you think he can help you're drive for championships.