Given the logjam at the 4 (Davis, Aytes, Dastrup, Childs, Hartsock, etc.) I'd be shocked if Mika played the 4 as well.
Going forward, the idea will be to get Dastrup and Mika on the floor at the same time. Dastrup is definitely more of a 4 than Mika is. He already has a nice mid to long range jumper.
While Mika's position at the next level is definitely PF, he'll have a chance to develop a jump shot while playing the 5 in Rose's system.