I'll give my take on the Collins situation. First, let me acknowledge that I honestly don't know because I've never been to a meeting with the staff.
The focus is on that Collins hasn't had a chance at T because we haven't seen or heard about it. You've got all sorts of evaluation tools that go on during camp. It has been said that he doesn't have the footwork to perform there now. He projects better at G. They prolly took one look at him in drills and knew he wasn't capable or ready.
Just because he performed there in college is not really an indicator that all doubt has been removed that he will dominate at the next level. He seems real natural at G from what little I've seen. Maybe they want to push Leary? I'd like to see if what they are seeing in practice with the other guys can develop. I'm guessing they have more natural ability for the position and are hoping they will develop into something game worthy. Where Collins is just a raw, strong badass.