Well, yeah. Batum looked absolutely lost in summer league. Most coaches wouldn't have started him the first game based on that.
Webster was out for the season, so McMillan was going to start Batum instead of Outlaw in the first game. As I recall, Nate backed off and said, that's too much pressure for a rookie. Anyway, Batum was a rookie starter because of necessity, not because of McMillan's generosity.
At that point Webster was only supposed to be out until December and Outlaw was considered to be good enough to handle the spot for a month. But Batum stepped up his game in camp.