Of course you pick the kid, then you play him 25-30 mpg to make him a ROY top candidate, and move him for a good pick in 2014... unless, of course, Shabazz comes as humble and willing to learn as you would like in a Celtic player.
If Gerald could be a part of a package to get a superstar, with some luck you could turn Shabazz+Bass into a great pick/young player.
Of course, longterm, I'd rather pick Saric.