I'm well aware that Duke has Jahlil Okafor.
More importantly, Turner is well aware of that, too, and he still has Duke in his final seven. Thus, let's at least explore the studio space here.
Duke's backcourt is more loaded than a baked potato from your local steakhouse, but the depth in the frontcourt is a bit lacking. Aside from the incoming Okafor (6'11") and Justise Winslow (6'6"), the only players on the roster taller than 6'4" are Semi Ojeleye (6'7"), Amile Jefferson (6'9") and Marshall Plumlee (7'0")—and Ojeleye and Plumlee played sparingly last season.
Jefferson and Okafor starting in the post works just great, but where does Duke turn when those guys need a break or get into foul trouble? Playing small ball is always an option—and arguably a better one than banking on getting quality minutes from Plumlee on any given night—but getting Turner would be the best option of all.
Duke has always been at its best with a stretch 4 on the court (Ryan Kelly, Kyle Singler, Shane Battier, etc.), but what about a stretch 5 playing the 4? Feel free to call him a power forward or a second center, but Turner has the ability to step out to the perimeter to get his buckets.
Having him and Okafor in the starting rotation with Jefferson coming off the bench feels like the type of lineup that might actually be capable of slaying the mighty Kentucky.
It would be an incredible fit for Duke, but it might not be great for Turner's NBA prospects.
There isn't much demand at the next level for 7' guys who prefer to play on the wing. There's a reason we inevitably end up comparing every tall guy with a three-point stroke to Dirk Nowitzki, and that's because he's virtually the only marketable one.
Anthony Davis was a great three-point shooter in high school, but he abandoned that aspect of his game in college to focus on his interior game, becoming the No. 1 pick in the 2012 draft. Turner probably wouldn't be challenged to do the same if he has Okafor to handle all the grunt work.