Yes, I can. Here are your points:
Middlebrooks played SS in HS so that is where he should play now if they try and force him into the lineup, not LF.
HS was 5 years ago. He hasn't played SS or OF since then. When playing someone out of their normal position, I choose a less critical position, ie LF. This is a valid dispute. The fact of their histories does not preclude consideration of their current play and mitigation of the impact of the learning curve, which is what I'm doing. No, I can't dispute that it is a fact that he played SS in HS. I can dispute it's relevance to right now, and I am.
He misread a flyball off of his bat.
If I made decisions off of one anecdotal situation, I'd make a whole truckload of impulsive and wrong decisions. I don't care that he misread a fly ball off of his bat. You see very good defensive OF do this all the time. No matter how many times you bring this up ad nauseum, it proves nothing. I dispute the relevance of this evidence.
What else is there besides your opinion, which I place very little value on, that he won't be good enough to be acceptable out there?