Here is a picture I found which shows a second baseman about to turn a double play. Notice his mistake?
If you are not sure, look at this Chase Utley photo doing the same thing. See the difference?
The young player up top will waste precious time after catching the ball. That is because he will have to take his bare hand that is incorrectly positioned behind his glove and bring it all the way around to the pocket to get the ball out. Chase Utley, on the other hand, already has his throwing hand positioned close to the pocket (thumbs up like they should be! Click HERE for that explanation) so he won’t waste that time. He takes care of that hand’s position before the ball is even caught.
There are a boatload of little things that go into successfully turning a double play. This is one of them.
FYI: I’m planning on doing a full seminar just on turning two in the near future!