Why isn't Evan Turner starting?

Although I am both elated and optimistic about this current Sixers team, there is one thing that bothers me every time the starting lineups are announced before each game: why isn't Evan Turner starting? Yes, I feel stupid to even question Doug Collins for a second. He has proven to be exactly what this franchise needed. But why isn't our 2nd overall draft pick from two years ago, who has shown massive improvement in his all-around game, still coming off the bench behind Jodie Meeks, who is exciting to watch yet painfully streaky? Is it because, with Lou Williams and Meeks coming off the bench, would you have two almost identical, one-dimensional players subbing in as big pieces off of the bench? Or is it because Collins simply believes Turner's talent and skill level have him unworthy of being in the starting five?

While Turner can't light up the scoreboard quite like Meeks, he drives very well to the rim, is an excellent rebounder for his size, has an above average jumper, and plays superb defense (which that, alone, stuns me as to why he isn't starting for Collins). While his shooting has undoubtedly improved since being drafted out of Ohio State, his defense is what has really turned me into a huge Evan Turner supporter. I was in attendance at the Bulls game last night, when in the first quarter it seemed like Kyle Korver was going to have one of his typical stellar shooting nights. If he wasn't wide open, he was blowing by Meeks and pulling the trigger on a quick catch and shoot. Alas, in came Evan Turner, and Korver went only 1-5 the rest of the game. Now Korver is obviously far from being a superstar (speaking of one-dimensional players), but as Sixers fans we all know he is more than capable of having big scoring nights. Turner took a lot of heat his rookie year, and deservingly so, but this year he has increased his shooting percentage from .425% to .465%. He has also averaged about three more points and three more rebounds per game than he did last year. Mix 10 points, 7 rebounds, and 3 assists per game with some lockdown defense and you have yourself a more than qualified NBA starter over Meeks. And while Turner is not short on confidence or basketball intelligence, you have to figure keeping him on the bench isn't doing him any favors. Then again, who the heck am I to question Doug Collins?