Well, let's try this by way of analogy.
1) You know you are going to buy a car. You're leaning toward a particular vehicle but you'd like to try two other competitor vehicles. (Miller knows he is going to play college basketball. He may be leaning towards a particular school, but he has offers from a couple of other schools and he wants to make a more informed choice.)
2) You visit three dealers with the three different vehicles on one Saturday and test drive all of them. You tell the salesmen that you will make a decision and buy a car by the following weekend. (Miller takes three campus visits and announces that he will make his decision within about a week and a half.)
3) After the test drives, you spend the week doing more research on the vehicles. (Miller spends another week researching the schools and basketball programs and discussing the matter with significant persons).
4) You make your decision and purchase the car the following weekend as planned. (Miller announces his decision on May 10th).
Hopefully, you now see that there is nothing "puzzling" or "odd" about this behavior