I hear you Sammy.....but my frustration is that I am in a situation where I can't start my starters for fear they will get too many minutes. So I am kind of stuck in no mans land, and that is not realistic. You are right, actual game time is the best way to bring a young guy up, but not being able to play my starters is not realistic. Like you said about Lebron, He had 88 minutes in two games.....does that mean that his game shape would automatically suffer for his next game? In Lebrons case, perhaps maybe so with the bad elbow
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But by and large, 90 minutes, let alone 75 minutes in two games wouldnt hurt a younger players performance.
Another case, is that in my game, I had a 10+ most if not all the 4th quarter, there were multiple times that it would have made sense to bring in the backups. But you never see an NBA player all of the 1st half. I can see leaving backups on the bench in the 4th quarter of a close game....but in the `1st half, you do your normal substitution pattern and make adjustments in the 2nd half. Even in important games, the backups will spell the starterrs for at least a few minutes.